We were in Puerto Montt, at the northern edge of Chile's vast Patagonia region, folding ourselves into a single-engine plane for an hour flight through narrow mountain passes, when I turned to Yvon Chouinard with a sudden thought: "Hey, Y.C., on this trip if something happens to us, we're covered by Medicare."

He groaned, reluctantly acknowledging that we were now well into our 60s, setting off on another trip into a wild and remote place at an age when we're eligible for senior discounts and early-bird specials. Yet, here we were, flying through heavy fog and low-lying clouds, often no more than 50 feet from the whitecaps of a southern Chile fjord, buffeted by winds so strong Malinda, Yvon's wife and business partner, was frantically searching for a barf bag.

It was in many ways the beginning of our new lives together, and an extension of an old, slightly odd friendship. I am a New Yorker with more suits in my closet than I care to admit. I move easily between television studios and the White House, mingling with presidents, despots, moguls, robber barons, movie stars, and poseurs. I am tall and talkative.

Yvon is short and reserved. I don't think he owns a suit. He lives hard by the sea in California, where his friends tend to be dirtbag climbers, surfers, expert fly-fishermen, environmental activists, and fellow iconoclasts. He travels widely in search of bonefish, steelhead, and salmon, as well as great waves and walls of rock and ice. His politics are much more radical and pessimistic than mine. He's also one of the best friends I could ever have.

Yvon and I have been getting together for 25 years, since I first met him in Jackson Hole when he was already a legendary rock and ice climber, the inventive genius behind modern climbing gear. He's the founder of Patagonia, the clothing company for everything from winter mountaineering to kayaking to fly-fishing. We were first introduced by our mutual friend Rick Ridgeway, a member of the first American team to summit K2.

Rick and Yvon gave me a short course in rock climbing (very short) and we set off to climb the Direct Exum route on Grand Teton. I was roped up between the two of them and made the summit, too naive to realize what they had put me through with so little training. It was the beginning of three decades of annual excursions with the same formula: Take a step and drag Tom.Yvon still has the same short, muscular body, and a deep, permanent tan from years on rock and ice and water. Although he hates being known as a businessman, he's also an exceptionally successful retailer.

This would be our third trip into Patagonia together, the first for me on the Chilean side. We'd been talking about it since I began plans to step down as anchor of NBC Nightly News, a move he'd been badgering me to make for the past five years. As much as I admired Yvon for his ability to run a successful business and still make time for all the fishing, surfing, and skiing, I wasn't sure I could work out the same balance in my life.

This trip would be a test of sorts. I had almost left the anchor desk in mid-2001, but when 9/11 happened I couldn't walk away from one of the biggest stories of my life. Now that I was free, a trip to Patagonia was the logical next step. In its mountain ranges, glaciers, rivers, and lakes, it is the essence of freedom from pavement, stoplights, $12 martinis, and cell phones. For me, Patagonia is the premier getaway destination: little more than an overnight flight from New York; vast, sparsely populated coastal regions, plains, and mountain ranges; trophy trout fisheries; exotic flora and fauna; and a kaleidoscope of weather conditions that sharpen the senses and stir the blood.

Yvon, Malinda, and I would be meeting our friends Doug and Kris Tompkins, both former ski racers and children of the '60s who managed to combine the zeitgeist of that era with a shrewd sense of business and a passion for conservation. Doug and Yvon have known each other for 45 years. They met climbing in New York's Shawangunk Mountains and quickly discovered a shared taste for personal risk and a kindred entrepreneurial spirit.

In 1968 they spent six months driving from California to the tip of South America, climbing, skiing, and surfing along the way as they headed for Fitz Roy, the towering and forbidding granite spire on the Argentina-Chile border. Because of Fitz Roy's notorious weather, they were holed up in ice caves for weeks at a time as they awaited their chance to put in a first ascent on the southwest ridge.

In the cold and dark recesses of Fitz Roy's approach, they came up with two ideas to finance their passions: Yvon would shift the focus of his climbing hardware business to clothing and call it Patagonia. Doug and his first wife, Susie, would turn their fledgling clothing line, Esprit, into an international retail giant.

Yvon is still running Patagonia, but in 1990 Doug sold his share of Esprit for more than $100 million and moved to Chile to begin his quest for a sustainable life that sits lightly on the land, preserving and restoring rather than damaging and destroying wild places. Both men are mindful of the limits of their remaining time and the work still to be done. Aging warriors of rock and ice, whitewater and deep snow, pressing on to secure what high ground they can in a part of the world that forever has a hold on them.

Kris McDivitt was CEO of Chouinard's company when she fell in love with Doug, just after he began his South American conservation crusade and persuaded the Chouinards to join him. Doug and Kris divide their time between Chile and Argentina, where they have formed foundations and, with the Chouinards, have jointly committed big chunks of personal wealth to buying and preserving huge tracts of Patagonian rain forests, rivers, lakes, and mountains.

Doug's Conservation Land Trust has already created a new national park and handed it over to the Chilean government. It's called Pumalin, a 700,000-plus-acre preserve. That's where we were headed first, if we could find our way through the heavy weather. After a flight at wave-top level over Fiordo Reñihué our pilot poked the nose of the Cessna 360 through the cloud banks and fog of landfall and decided we could make it to the grassy strip alongside the Tompkins' compound. As we rolled to a stop in a driving rain, Kris emerged, laughing and saying, "Yvon, you always bring this weather."

Personally, I was thrilled. If you go to a rain forest, bring it on. Besides, the combination of rain, low-lying clouds, and wispy fog against the backdrop of a deep green woodland and somber granite outcroppings only enriched the natural aesthetics and amplified the quiet. It's easy to see why Doug and Kris are so content here. Their Pumalin home is organized around the kitchen and a big wood-burning fireplace. Dinners are simple and hearty: lentil soup with lamb sausage, robust Chilean red wines, home-baked bread.The next day the weather is still low and wet, but Doug is sure he can fly, and he's eager for me to see the small farms he's developed on the perimeter of the park. The two of us roll out one of his Huskies, a single-engine plane that's the air equivalent of an old Willys jeep. It will land just about anywhere.

First we hop over to his organic honey operation, a state-of-the-art processing plant and shipping shed where local residents are learning new skills and finding steady work. Not so long ago the region was marked by the slash-and-burn attitude of absentee cattle and sheep ranchers who provided only seasonal jobs as they destroyed the forests to make more room for grazing pasture.

Next, we buzz off to another farm rebuilt with the same sensibilities as the main compound – shingled buildings that blend in with the surroundings. Veronica Orias, an enthusiastic and handsome young botanist, is in charge of the tree farm, and she's having uncommon success growing alerce seedlings and other native trees for replanting in the burned-over areas.

Veronica has guests, two uniformed officers of the Chilean national police force, the carabineros. It's a friendly visit, and when they recognize Doug they're eager to have a picture with him, an encouraging sign of the changing attitudes in Chile toward this outsider who moved in and began buying up everything he could get his hands on. After years of suspicion about his motives, fueled in part by his brusque personality and aversion to publicity, Chileans are now beginning to understand and appreciate his altruism.

Before heading home, Doug turns the Husky toward the upper reaches of the park, a series of steep valleys bordered by snowy peaks that may never know the hand of man. The approach to them is ungodly: raging rivers bordered by thick rain forest.

In the backseat of the tiny plane I am overwhelmed by the primal beauty and remoteness of it all. Doug maneuvers through the weather and downdrafts with grace and confidence as he explains over the headset, "Only about 2 percent of the park is accessible, but we've built a visitors center and trails at the entrance. The important thing is, all this will be forever wild."

I've never seen him so happy or so contented. A handsome, compact, and thoroughly athletic man, he's always been known for his no-detail-is-too-small standards and, equally, for his impatience with anyone who doesn't measure up. His intensity remains, but it seems to have been leavened by his understandable satisfaction with what he's accomplishing.

We're flying so low and slow I can practically count the petals on flowers. Doug's bush pilot skills are impressive, but later I hear some terrifying tales of flying in the Andean turbulence. He took a visiting photographer up and ran into weather so violent they were forced into an unscheduled landing. The photographer dropped to his knees and kissed the ground, then realized he was missing a camera. They looked everywhere before Doug discovered a camera-size hole in the plane's Plexiglas sunroof. The camera had been ejected by the force of the turbulence.

Our flight, I am pleased to report, is trouble-free, and I return in time to join Yvon in exploring the fishing prospects on a river alongside the main house. It is packed with rainbows, none much larger than 12 inches, but all of them in fighting trim and little affected by the driving rain and high water.

Later, at dinner, we all fall into a conversation about something that had never come up in all of our previous excursions. It began with Doug asking about the new phase of my life, post–Nightly News. I said I was still adjusting to the absence of daily deadlines and the realities of having just turned 65. I likened my old life to that of an airline pilot. I'd get up early every morning, be handed a flight plan, crawl into the cockpit of daily news, and fly a fixed route to 6:30 every night. Now, I said, I still get up early, but I have to file my own flight plan and the takeoffs and landings are a lot more irregular.

Malinda and Kris join in as we discussed the effect of statin drugs, estate planning, contingencies if one mate goes before the other. Yvon says he'd live a much simpler life. "I'd go somewhere where I could just fish and trade my catch for some rice and other staples." I didn't doubt him, but I didn't think I'd be joining him, either.

But the frank discussion of entering the mortality zone was useful and, for me, another reminder of how much these friendships have meant. The Chouinards and Tompkinses take me to places I may not otherwise go, physically and philosophically. Sure, Yvon has steered me up Grand Teton, and I made it to the top of Mount Rainier via the Kautz Glacier with Doug and Yvon. We were all part of a gonzo kayak trip down a little known river in the Russian Far East. Yet, looking back, as physically demanding as those and other trips were, it was the idea of them and the bonds we formed that linger. They called themselves the Do Boys, and I was happy to be a conditional member.The next morning the Chouinards, Kris, and I leave Doug behind to manage his sprawling empire, and we head south to Valle Chacabuco to take a pack trip on the 175,000-acre estancia that Kris, Malinda, and Yvon have purchased through their foundation, Conservación Patagónica, for another national park. It's a six-hour drive on a twisting gravel road, dodging heavy trucks loaded with sheep and wool. But as we wind around Lago General Carrera, a lake almost twice the size of Tahoe with none of the development, the vistas remind me of what the American West must have looked like in the mid-1800s. It was as if we are driving from Glacier National Park, around Flathead Lake, past Monument Valley, and through Jackson Hole all in one day. Only everything – the mountains, the lakes, the rivers – feels larger by half.

At one dramatic overlook, we are unexpectedly joined by a lean bicyclist from London pedaling a sturdy bike and towing a small-wheeled cart packed with his camping gear. He's a cheerful chap, understating his ride that day as a "bit of up and down," which is how he might also describe the road between Aspen and Denver. He says he worked in finance and information technology in London. "I got to thinking," he says, "if not now, when will I do this?"

He is headed for Alaska. I ask how much weight he'd lost so far. He laughs and says, "Not much; I'm a lean bugger. I'm a mountain-bike racer on weekends back home." He wants to know about the road ahead, which we'd just covered in our four-wheel drive. I try to remember. Was it mostly up or mostly down? He laughs again, putting us in our place. "You'd bloody well remember if you were pedaling and not riding in the car!"

We also met a truckload of American kayakers who had been running local rivers. When I introduced them to Yvon, they brightened with recognition of this legendary adventurer. I was reminded of another meeting with a young American climber when we were en route to the base camp of Fitz Roy. She was relieved to encounter Yvon because she was sure he'd persuade her two Brazilian climbing friends not to try a daunting ice face; they'd never climbed ice before.

Yvon heard her plea, then listened to the macho Brazilians make their case. I knew what was coming. He thought for a moment and said, "Hell, I think you should go for it." I laughed and said to the young woman, "Don't ever ask this guy for help in backing down."Juan Luis, a manager of the sprawling Estancia Valle Chacabuco, is 6-foot-4 and a seasoned ranch hand. He grew up in these valleys and mountains, and is a rare combination of gaucho and modern manager who speaks French as well as Spanish. Every year as a boy he rode horseback five days north through the Andes on his own to a boarding school, and then back again for the holidays.

For our pack trip he's brought along Pablo, the estancia's house manager, and Francisco, a former homeless urchin from the nearby village of Cochran whom Juan Luis has more or less adopted and made into an accomplished gaucho.

Riding horses is the one outdoor activity in which I can claim some superiority over Yvon. He sits atop a horse in a crabbed posture, wondering, I always imagine, where to set up his rappel. I remind him to keep just his toes in the stirrups and his heels angled down. We're wearing hiking boots with lug soles, and bailing out could be a sticky problem.

It's my 30-second riding lesson, a payback to Yvon for his 30-second crampon lesson as we began our ascent of Mount Rainier and his five-minute kayaking lesson just before we headed into Class III water near Jackson Hole. On that occasion the river was swollen with runoff, and we hadn't gone far before I turtled. As I shot down the stream, hanging on to the boat with one hand and swimming with the other, Yvon paddled over to hear what I was shouting. He got wide-eyed as I said, "Hey, we forgot something: life jackets." Fortunately I am a strong swimmer with a high threshold for foolishness.

The estancia horses are strong and steady as we climb more than 1,500 feet up narrow trails and steep banks into a canyon framed by towering rock walls. Above us are nesting sites for the famed Andean condors, the giant birds with 10-foot wingspans. By noon we've reached a gaucho campsite and, as we have to be back on the road tomorrow for flights home, we dismount and set up a comfortable base. No freeze-dried mac and cheese or PowerBars in this country: Francisco unwraps a lamb quarter and sets up an asada as Pablo uncorks a robust red.

Yvon and I set off to explore the canyon, which is divided by a fast-flowing river with no natural crossings. Working our way up the west side, we come to a furious little tributary and, with some effort, rock-hop across the fast, deep pools. Somehow – and this happens more often than not on our excursions – we get separated as Yvon ambles off in one direction and I in another. I make my way through a mossy stand of old-growth beech trees until suddenly I am on a substantial rock slide, big boulders that have tumbled off the cliff. I start across until I remember my friend Aron Ralston, the climber trapped in Blue John Canyon for five days until he cut off his arm and managed an epic escape.

Having documented Aron's ordeal in a two-hour prime-time broadcast, I am all too aware that should I be similarly trapped I'd die like a pathetic weasel. So rather than take that chance, I retreat to the little tributary and the rock-hopping crossing. Alas, my launching boulder has taken some extra waves, and as I step onto it for the graceful leap across I go ass first onto its slick surface and into the icy stream. And so does my camera, with the only clear-weather pictures I had.

Yvon shows up back at camp about an hour later. I had been secretly hoping he'd encountered a similar problem, but nope, as usual crossing the stream was routine.

By dusk, the lamb was almost cooked through. In the twilight sky first eight, then a dozen, then 20 condors began a lazy ride along the updraft, their wings carrying them by the sheer cliffs and down the canyon. I raised a glass of Chilean merlot to their primal origins and quietly vowed to return to this spiritual place. I fell asleep in the crisp night air wondering, Will Yvon and I ever leave the sleeping-bag portion of our lives completely behind?This had been a mellow outing for the Do Boys, in part because of the heavy weather in the mountains and the limited amount of time. But, as always, it will stay with me long after I return to my world of pavement, high-rise buildings, and stacks of phone messages. The Patagonian landscapes linger, but so does an unexpected meeting at the beginning of the trip.

The Wharton School, the University of Pennsylvania's business school, runs an Outward Bound kind of program, and this year two dozen students were fording rivers and camping near Doug's Pumalin Park.

One morning they gathered in a conference room at one of Doug and Kris's farms, most looking waterlogged, a little sleep-deprived, still wearing their caps and fleece jackets to ward off the damp cold. They were about to hear an unconventional lecture from Doug and Yvon, two wildly successful businessmen, about their passion for conservation, restoration, and temperance in consumption.

It was at once an incongruous and yet encouraging scene. Most, I guessed, would end up in power suits and designer outfits in sleek urban offices, but they were quiet and attentive, a few taking notes. Doug began by describing how he bought his first 17,000-acre Chilean property (for the price of a San Francisco condominium) after deciding that at Esprit he was part of the global problem because he was selling more clothes than consumers really needed.

Now, he said, his goal is to save what he can of this precious planet by conservation and reforestation. The small farms are an important part of the plan because if he can make the local honey and tree-nursery businesses succeed, it will wean this part of Chile off the global economy, which has such a voracious appetite for natural resources. It's a work in progress, he emphasized, but he's plainly at peace with that progress. As he told the Wharton students, "There's no right way to do the wrong thing."

Yvon talked about Patagonia's decisions to dedicate 1 percent of its total sales to saving the planet and to reject pesticide-heavy regular cotton and convert to organic cotton when everyone said it wouldn't work. "We were like alcoholics," he said. "We needed to take the first step by acknowledging we're polluters. Every time we've decided to do the right thing, we've made money. As David Brower once said, 'There's no business to be done on a dead planet.'"

Then he said, to general laughter, "The three of us are going to hell, but we still have a chance to get some things right before we get there."

When my turn came I said, "Remember, these two guys have had great lives, they've had fun and made lots of money. But in the end their business careers will be about much more than making money – that's what you have to remember in your own careers." Then I added, "They may still go to hell, but I don't think I'll go with them because somehow they'd manage to find the hottest corner."

Maybe we can just work out something for eternity in a corner of Patagonia.