Fields of blue lupine and lonesome alpine lakes 10,000 feet up the Colorado Trail aren't what make this the nation's most spectacular mountain-bike ride: It's that you aren't lugging a 40-pound supply pack. The San Juan Hut Systems offer the only hut-to-hut mountain biking in the U.S., with routes for various skill levels. This route from Durango to the slickrock of Moab, Utah, is 215 miles of switchbacks and 3,500-foot ascents, splashing into creek bottoms, and kicking up the red dust on old mining roads. The biodiversity is unmatched: forests of aspen, newborn elk, vistas across two states. At the end of each day, a cabin awaits (six in all, about 30 miles apart), with everything you need: built-in bunks, fresh water, fixings for pesto-chicken dinners, Larabars, Coors, and jars of ibuprofen.

There are no guides, just you, keys to the cabins, and topo maps. It's not a pampered sag-wagon adventure. It's all-out freedom.

Getting there: After flying from Denver to Durango, start the trail at the Durango Mountain Resort. Register early for the seven day–six night $895 journey.