When I was 15 my family sailed from Santa Cruz, California, to Hawaii. Fourteen days out my father, who was navigating with a sextant, announced that we had another 500 miles to go. So it was something of a surprise when the cloud-wreathed mass of Haleakala Crater, the dormant volcano that forms the eastern half of Maui, reared up out of the sea the very next day. For me the real shock was the exhilarating upsweep of those high green islands, like someplace I'd imagined but never seen yet.

Clearly I'm not the only one Hawaii has seduced. More than 7 million people visit the place every year. Wide-bodied jets from the mainland fly nonstop to four islands now, and the state's hotel occupancy rates are second only to New York City's among U.S. destinations. It's hard to get away from it; round a corner on a wild coast road and, sure enough, there's another pale face, what the native Hawaiians call a haole, in a shiny Dodge Neon coming the other way.

I didn't want to be the haole in the rental car; I wanted to get off the path and see a less packaged, more primeval place, the raw Hawaii that geologists say is still emerging, eruption by eruption, from a "hot spot" in the middle of the Pacific plate. So on New Year's Day I flew to Hawaii with my friend Randy Harris, a wicked hangover, and an ambitious plan to traverse the two youngest, largest Hawaiian islands. We would cross Maui on foot and circle Hawaii, also known as the Big Island, by bike, topping out on two of the island chain's three major volcanoes. Except for a bit of thumbing on day one, it was going to be human power all the way.

It made sense to start on the far east side of Maui, where Haleakala drops down to an untrafficked, Edenic coast. Haleakala would be a warm-up for our ultimate destination: the Big Island's still-active Mauna Loa, a 30,000-foot seafloor volcano that may be the biggest mountain, base to peak, in the world. Of course, only the top 13,600 feet protrude above sea level, but that's enough for it and its virtual twin, Mauna Kea, to draw the occasional wintertime blanketing of snow.

Hawaiian snow! I didn't know why the idea drew me so powerfully, but I wanted to be there when it happened, to crunch around and feel firsthand the power of a place that, smack in the middle of the Pacific Ocean and a mere 20 degrees north of the equator, could nevertheless reach so high as to call down that kind of a blessing upon itself.

That first morning, though, our plan to escape the haole hordes didn't go so well. Lacking a vehicle and short on time, we'd planned to hitchhike the first leg, the 37-mile Haleakala Highway, which climbs from sea level to 10,000 feet. The only problem was that nobody stopped. "Wow," said Randy, as the sun climbed higher and we began to roast. "This kinda sucks."

We'd reached the point of despair when a kid named Ryan pulled over in a big flatbed loaded with plastic bins. There was no public recycling on Maui, he explained; he was a private hauler heading up the volcano to pick up Willie Nelson's empty beer bottles. "But hey," he pointed out, "at least we're burning biodiesel."

On the way up, Ryan gave us a different view of Hawaii from the tourist board's. He said there was a distinct anti-haole vibe in Kihei, where he lived. More than a vibe. Local kids threw rocks at tourists if they drove down the wrong street. That was old hat in Hawaii, of course, where massive development seems not to have done much for the descendants of the original inhabitants, and resentment consequently runs deep. A new wrinkle, he said, was the ice problem: crystal meth. Surprisingly, it wasn't young people who fell prey so much as 30- and 40-somethings, "people with no jobs or dead-end jobs."

Ryan blew right past Willie Nelson's homestead and took us all the way to the National Park entrance gate at 7,000 feet. We got out and stretched in the now cool air, breathing in the pure oxygen of the trade winds. A rainbow broke over the flank of the volcano, and for a moment there, it felt almost like old Hawaii. Then a fat-tired train of "downhill cruisers" came tootling by, in absurd full-face crash helmets and matching light-blue windbreakers and windpants. At the head of the line their guide put his hand up – not waving to us but telling his charges to slow down.

From the parking lot at the end of the highway it's about 10 steps to the glass-walled observation platform that squats on Haleakala's summit. Inside, shivering, underdressed women clung to their boyfriends and peered down into the gaping, Manhattan-size crater – actually a mountain ridge blown open on two sides by eruptions. Outside, Randy staggered around trying to take pictures of a ranger holding a wind gauge (gusts to 54 mph, he told us). Randy's pale New England skin was already turning an alarming shade of pink, as he'd neglected to bring a hat, sunglasses, or sunscreen, and the sole of one of his shoes was falling off. "Uh, do you have any strapping tape?" he'd asked earlier that morning at the park entrance station. The ranger there, who'd just finished grilling us on our backcountry expertise, eyed him coolly. "Sure," he drawled. "On the cinders, it should last about 20 minutes."

I wasn't worried. The apparent chaos was all part of Randy's MO, and you couldn't argue with the results. Within a few minutes of heading down the crater trail he was shooting a beautiful Swiss tourist as she slathered her arms with sunscreen. An hour later he was at it again, persuading a stylish Russian day-hiker to paint herself with a vermilion-colored stone.

That night, after a 10-mile hike through an alien landscape of red and black lava flows, towering cinder cones, and "groves" of a tall, gray-green lobelia-like plant known as silversword, we camped under the crater's steep western escarpment. I pulled on all my clothes, climbed into a fleece sleeping bag liner, and still froze. The next day we set out to climb Hanakauhi, a great triangular peak on the far side of the crater. Woozy from too much sun, Randy bailed halfway up. I topped out after a long, satisfying scramble along the airy summit ridge. A tourist helicopter clattered past, then circled back for a second look.

We stumbled down the Kaupo Gap the next day, thighs cramping and toenails dying as we dropped 6,400 feet through every conceivable microclimate on the planet. Silversword gave way to scrub; then came ferns and cloud forests, home to the last few native Hawaiian birds. (The mongoose, brought in to control the cane rats, wiped out most of the island's birds as well.) Finally we were out of the park and walking through eucalyptus groves and a cattle ranch, toward the whitecaps of the Alenuihaha Channel. Resting at a water tank, we met a Hawaiian cowboy named Peter, a beefy guy in a camo jacket riding an ATV. He'd moved to Kaupo, population 40, a couple of years earlier.

"I can't take it over on that side no more," he said, gesturing in the direction of Kahului, Maui's main city.

"A little too whited-out?" Randy asked.

"You got that right. All those airplanes, one after the other."

Even if we'd wanted to drive the last 16 miles to Hana, on Maui's eastern tip, we couldn't have. There had been a big earthquake in October, and the road from Kaupo, the only road around the south side of the island, was closed even to foot traffic. We stepped over the roadblock and saw why. Several huge boulders had fallen from the cliffs above the roadway, pulverizing the guardrail. We picked our way carefully beneath the overhangs at first, then just went for it in one full-on sprint, laughing like maniacs to hide the fact that we were scared shitless.

Safe on the far side, we grinned as couples in new Mustangs and Jeep Wranglers stared forlornly at the road closed sign. To get back to the condos and hotels of West Maui, they were looking at a U-turn and a four-hour reprise of the infamously twisty Hana Highway. "You mean there's no other road?" one woman asked plaintively, as if it were our fault.

Archaeologists say Hawaii was one of the last places on earth to be settled, probably around a.d. 900 by Polynesians sailing north from the Marquesa Islands in double-hulled voyaging canoes. When the first European, James Cook, arrived in 1778 – blundering into the islands much as my father had – he was greeted as a god, but soon wore out his welcome; an irate mob backed him into the waves in Kealakekua Bay, a few miles south of present-day Kona, and ran him through with a spear.

Randy and I hoped for a slightly better reception when we hopped a puddle-jumper over to the Big Island from Maui. Kona today is a distressingly generic place – box stores and strip development – but Chris Huber, a bike shop owner and former Coors Light team racer who set us up with mountain bikes, told us that beneath the placid exterior lurked plenty of tension. He had had car parts stolen, has been hassled while out riding, and in general was used to getting "big stink-eye."

We took a day to dry our gear and restock. At Wal-Mart Randy bought flip-flops and, perhaps hoping to attract some stink-eye himself, a floppy Panama Jack hat. That night we stole some milk crates from behind a Safeway to serve as makeshift panniers. Thus equipped, we launched south on Highway 11, the Hawaii Belt Road. It wasn't quite the cruiser route I'd been hoping for. The climbs were grinding, the heat unrelenting, and the "vog" – a kind of volcanic haze peculiar to the Kona coast – dispiriting. But at Captain Cook we turned off the Belt Road and plunged down to Kealakekua Bay, and suddenly Hawaii was beautiful again.

Swimming off the dock of the bay we met a group of schoolkids speaking a strange, mellifluous language: Hawaiian. Their teacher, Kalani Soller, an amiable 37-year-old with impressive Polynesian-style tattoos on his arms and legs, told us they were from Kau, on the windward side of the island, one of the last pockets of traditional culture on the Big Island. Soller pointed out the monument across the bay marking the spot where Cook had died. "It's kind of a joke we have with other Polynesians," he said. "Hey, you didn't take care of the guy, so we did." He smiled, then grew wistful. "He should have kept going and never stopped here."

We got as far as Hookena, where there's a little county park on the beach. That morning's newspaper had called Hawaii's homeless problem the fourth-worst in the country; looking around at our ragged fellow campers it wasn't hard to believe. A guy who called himself Pugsley came by to bum a smoke. "I need to get a job tomorrow," he said, eyeing the microwave burritos we were reheating on the stove.

"They're hiring at the Subway in Kona," Randy said helpfully.

"Nah, I'm into woofing," Pugsley said. "Working on organic farms."

Fires sprung up on the beach, and the smell of pot wafted through the palms. A hapless security guard made the rounds, attempting to collect campsite fees.

"I don't pay," our neighbor said. "Why should I? Everywhere I am is the Hawaiian kingdom."

She was a sovereignty activist, an advocate for the idea of Hawaiian independence, and she delivered a long but entirely coherent explanation of how the Hawaiian monarchy had been overthrown by the United States in 1893, and why it now needed to be returned to its rightful owners, the native Hawaiians, who, according to the U.S. Census Bureau, comprise about 10 percent of the state's 1.2 million people. (She was not some lone freak; I'd heard much the same story from my uncle, a retired corporate lawyer who now lives on Maui. "Legally, the case is strong," he told me.)

At midnight Pugsley reappeared with glazed eyes and a warning about centipedes. "Hawaiian snakes, man," he said. "The brown ones hurt, but the blue ones hurt so bad you'll hallucinate."

"Thanks for that," said Randy, who didn't sleep the rest of the night.

In 1778, a few weeks before Cook's death, one of his marines, an American named John Ledyard, tried to climb Mauna Loa. Starting from Kealakekua Bay, his small party made it about 25 miles up the mountainside before a trailless forest and a lack of water stopped them.

I suspect that for Ledyard, as for me, it wasn't about "conquering" Mauna Loa, or even wanting a good story to tell. It was something much more primal, an almost physical need to feel the mass of the mountain beneath one's feet and to reach its tantalizing, unlikely, snowcapped peak.

But our plan was better than Ledyard's. Rather than take a direct frontal approach, we would spiral around to the wet side of the island by bike, using a national park road to get about halfway up the volcano's northeast ridge, and then hike the rest of the way to the summit.

The first day, starting from the beach below Naalehu, was a Tour de France-scale climb of 4,000 vertical feet – except that we weren't on 16-pound bikes. More like 10 pounds heavier. It was raining and Randy suffered big-time, riding the last five miles, after dark, in the back of a pickup truck.

Day two was even bigger. After a punishing 2,600 vertical feet on the bikes to the Mauna Loa trailhead, we still had another 3,400 to go. Darkness overtook us on the lava flows, and our lone headlamp was failing (until we replaced the batteries). When we finally got to Red Hill Cabin, elevation 10,000, the temperature was in the 20s. Miraculously, there were blankets.

I went to the summit alone the next day. All of Randy's clothes were soaked, and the ranger who'd issued us a backcountry permit had made a point of recounting hypothermia horror stories. It was 12.5 miles each way – pretty much a full marathon, at altitude, through a wilderness of lava and steaming cinder cones. At 12,000 feet I hit the snow. By the lip of the caldera, at 13,000 feet, it was six inches deep. I worked my way around the north side of the bowl and followed a series of snow-covered ahu, or cairns, to the summit, a giant ahu perched on the lip of the caldera's western wall.

Clouds smothered the peak; I couldn't see much more than the caldera floor, a black expanse of twisted lava pocked here and there by steaming vents. The big views came on the way down, when the clouds lifted and the setting sun illuminated the snowcapped summit cone of Mauna Kea, 30 miles away across the saddle of the Big Island. There were a half dozen structures clustered there, astronomical observatories, relay towers, and the like, and they made me somehow angry. Squatting on that great summit, they seemed sacrilegious – and by extension so did the whole idea of developing these islands for our 21st-century purposes. But what was the alternative? Independence or not, there was no turning back the clock.

For days we had been anticipating the last leg of our trip, the long descent to Hilo and the sea: 38 miles of pure downhill bliss. For the first two miles that's what it was. Grinning like idiots we zinged down the side of the volcano, ghostly ohia trees flicking by overhead. Then Randy pulled up. "Check out my back wheel," he said, shaking his head. "It doesn't feel right."

That was understating things. His tire was self-destructing under the load. We had no spare, not even any duct tape. We MacGyvered a fix, lashing parachute cord around the rim, but that meant the rear brake had to be disengaged. Randy lowered his seat and set off, flip-flops scraping the road like Barney Rubble brake pads.

Four miles later I got my first flat of the trip; a mile later, my second. Huber had supplied us with a handful of CO2 cartridges in Kona, assuring us they were better than a pump. Now they were all gone. I crept down the hill with exaggerated caution, but it was no use, and within a mile I flatted again.

I suppose I could have ignored the rental car that inevitably appeared, a hideous Chevy HHR, and the offer of a ride from its occupants, a very nice couple from Santa Fe. But pride has its limits, so I threw my bike in the back and hopped in. A mile before the Belt Road we caught up with Randy, staring mournfully at the shredded remains of his tire. With limited space in the car we decided to lock the bikes to a post and go have some mai tais in Hilo.

In the end, there was only one way to get the bikes back and still make our plane. As I signed for an electric-blue HHR of our own, I was amused to see that it cost less per day than the two bikes did. I can't deny that it was awfully nice to have a motor other than our own zipping us back up that 38-mile hill, with beer-holders on the console and a decent sound system to boot. It's just that after a while, it was kind of hard to tell if we were still in Hawaii.