We push up out of the forest and onto the pass, and the landscape sheds its skin. Shrugging free of moss and thickets and the dirt itself, bare granite stands braced against the wind and the sun and the last drops of rain, all beating down at once. Below us spreads a Patagoniac's fantasy: skies racing with heavy clouds; unclimbed, unnamed 10,000-foot peaks; waterfalls carving down hillsides of 450-year-old lenga beech trees; and the Cachet Glacier, glowing Slurpee blue, its pale cliffs calving ice into the dark cocktail of a lake called Cachet Dos.

It's October, early spring in southern Chile's Aysén region, and our ragged group of ten has been bushwhacking for three days, crashing through dense thickets of feathery coigue and ñirre trees, pulling on slick roots, spiny calafate bushes giving way beneath our boots. We've navigated horse-deep rivers, sustained sunburns and stomach flu, and cramponed over a wide, thick glacier. Now we stand panting on the pass, dazed by the switch from myopic forest to far-out vista.

"Uh, Jonathan," says Sun Valley, Idaho–based outfitter Scott Douglas. "This isn't a trail."

The announcement doesn't seem to faze Jonathan Leidich, our guide, who hooks his thumbs in his pack straps and beams. The 31-year-old founder of Patagonia Adventure Expeditions (PAEX), based in Coyhaique, Chile, Jonathan is an expat Coloradan who's spent much of the past eight years taking clients down the 40,000-cubic-foot-per-second rapids of Chile's nearby Río Baker. Between trips, he's hacked a world-class trekking route out of these high glacial valleys, the first trail through a remote, rugged national park called Laguna San Rafael. But before his first big group of clients arrives, he's invited down five friends from the States—including Scott, the one who told him about this area 12 years ago—and four guides-in-training. We're all here to test-drive the trail. Cool vision. Trouble is, none of us can see it yet. We look out and see trackless wilderness. Jonathan sees sustainable yurts and hot showers. He sees the Aysén Glacier Trail, a seven-day, 52-mile hut-to-hut work in progress that will be the first major new trail in South America since the iconic Paine Circuit, 300 miles to the south, sprang up in Torres del Paine National Park in the late fifties. Trekkers have made the 60-mile Paine one of the most famous walks in the world, but with up to 400 hikers a day, it's saturated. The Aysén Glacier Trail, Jonathan hopes, will become a northern alternative.

Extending 6,718 square miles from the Andes to the Pacific over the entire 1,622-square-mile Northern Patagonian Ice Cap, Laguna San Rafael National Park is nine times bigger and a hundred times emptier than 700-square-mile Torres del Paine. And unlike the Torres del Paine circuit, the Aysén Glacier Trail will stay empty. Only 17 trekkers, 12 guided and five independent, will be allowed to set out each day—all controlled by PAEX. Because the trail begins and ends on Jonathan's own land, because it passes through local gauchos' ranches on easements that Jonathan has personally negotiated, and because Jonathan is building the six yurt camps himself, the Corporación Nacional Forestal (CONAF), Chile's national-park service, has awarded PAEX an exclusive concession to operate the trail, the first arrangement of its kind in the country. The deal is designed, in part, to provide an alternative economy in a wild region that still sees more resource extraction than ecotourism.

For Jonathan, setting all this in motion has been no big deal, really: It's merely involved five years of bargaining with the Chilean government; the purchase of two ranches, 1,381-acre Palomar and 2,105-acre Sol de Mayo, on Laguna San Rafael's eastern edge; a sustained charm offensive eloquent enough to convince the gaucho populations of two river valleys, Valle Soler and Valle Colonia, to allow trekkers to pass through their land; the navigation of a constantly changing four-and-a-half-mile-wide route over the Neff Glacier; and the humping-in of enough tarps and tents and pots and pans and spoons and sleeping mats for six campsites. And then there's the boat. Establishing a crossing over the five-mile-long Lago Colonia—a glacial drainage that cuts off land access to the national park from Sol de Mayo—required the helicopter airlift of a 27-foot fishing boat, a two-week oxcart march to haul in the outboard motor, and a floatplane rental to fly in a new motor when the first one broke.

"Yeah, maybe I should just bag the trail," Jonathan jokes. He looks at Scott. "So," he asks, "are you sold on it yet?"

Scott looks around. No camps. No showers. No yurts. It's clear that Jonathan is way ahead of himself. But as all of us look over these peaks, we can't help being floored by possibility.

"Yeah," says Scott. "I'm sold."