ONE DAY, MY LIFELONG buddy Roo, short for Andrew, calls to say he has an idea. Not just any idea. A perfect idea, one that recalls the glory of our past adventures, from skiing clear-cuts in Alaska to childhood days jumping our Huffys—sometimes successfully—over a backyard trench Roo had dubbed the Pit of Death. His idea? We cross the Olympic Peninsula under our own power.

The Olympic Mountains are an exceptional mess; we know this because our families often visited them together. From Southern California to Alaska, the Coast Ranges rise smoothly from the sea in tidy folds, but at the Olympics, where glaciers once did the nasty, ridges and valleys swirl from 7,965-foot Mount Olympus like the tentacles of a jellyfish. Further confounding things, this maze exists in three heavily vegetative dimensions. At bottom is a beach. At top is an alpine region of shale peaks and more than 60 truculent glaciers. In between, a temperate rainforest full of more green and drippy biomass than the Amazon—and virtually every plant that has ever been bushwhacked. And while the peninsula is riddled with trails, there are no direct east-west routes. Most of them simply drown in the prickers surrounding Mount Olympus.

"One hundred and ten miles, five days," Roo says with a joyous cackle.

"Why five days?" I ask.

"It's all the time I can get off work."

"I love it," I say, blissfully unaware that the peninsula has been humbling explorers since 1889, when the so-called Press Party attempted to traverse its mysterious interior.

Funded by the Seattle Press newspaper, the six young trappers and frontiersmen who made this attempt possessed "abundance of grit and manly vim." First they tried ferrying their supplies upriver on a raft … which took forever (they progressed just four miles in almost two weeks). They built sleds … that didn't glide. Even their mule, Jennie, proved little help in the end, since she slipped above a steep ravine and plummeted to a tragic death. After five months, they had advanced less than 50 miles—and drunk all their whiskey.

Abandoning their siege tactics, each man shouldered a 75-pound pack and struck out on foot for the heart of the range—which turned out to be, depending on whom you asked, either "an exquisite panorama of mountain scenery" or "a damned rough layout." While bushwhacking through undergrowth so thick it was like "exploring a dark rat hole," they got lost and took a 12-day detour. They subsisted on "flour soup" for weeks. Nearly six months after departing, they finally rafted out of the mountains, lucky to be alive.

If we had known this, it might have given us pause. But not much. Because we'd still have had our secret weapon: tiny butt-boats!