In the months that followed my calf tear, even after the muscle had healed, nothing improved.

Thoughts from the day—­current arguments, past heartaches, the sentences that resisted being pinned to the page—drifted past as if on a conveyor belt.

Over a span of months that soon became years, I spent $20,000 on appointments and tests and unguents.

“A calf tear,” pronounced the sports-medicine doctor, bored by the mundane case before him.

I packed my car and headed east, into the Cascades, to a place with ready access to all the things I once did all the time: trail running, nordic skiing, backcountry skiing, mountain biking.

We pedaled 460 miles and 45,000 vertical feet in one week, up and down the byways of Colorado’s San Juan Mountains, through hailstorms that would strip paint off a Buick.

Friends came and went, as did success and failure, romance and loneliness.

Other neighborhood kids had to take out the trash for their allowance; my sisters and I ran for ours.

I saw physiatrists, osteopaths, orthopedists, and two vascular surgeons, who breezed in late, scowled at my legs, and left.

It was early September, just after Labor Day, one of those bronzed afternoons when the thermometer still says summer but the school buses and quickened pulse of the city suggest otherwise.

f this trip is a fool’s errand, I can’t think of better fools-in-travel than my companions. Dan, 45, is a smart-ass native of Northern California with sharp blue eyes behind his geek-chic horn-rimmed eyeglasses. A ball cap that hides a backpedaling hairline advertises Alaska Alpine Adventures, his 16-year-old company that guides trips ranging from ski-touring from a yacht to climbing in the Brooks Range and then floating to the Arctic Ocean in inflatable canoes. A few years ago, Dan also launched Adventure Appetites, a gourmet backcountry food company that has supplied the fare for our trip. Gabe, 37, from Washington, is an up-for-anything photographer whose goofiness makes it easy to forget that he’s a former mountain guide who has worked everywhere from the top of 8,000-meter Shishapangma to the unclimbed vertical walls of Ethiopia.

The fog machine is on full.

Recent studies have found up to 400 brown bears per 1,000 square kilometers. (By comparison, it's estimated that just 718 of the famous, feared Yellowstone grizzlies are sprinkled across 72,500 square kilometers in the greater park area.)

as if nature might evict them at any time.

Still more tundra, unspooling to a horizon so unbroken by man or mountain range that the sky would start at your shoelaces if only you could see them.

Black walls, black floor, black water, deep black holes and black vents; it fairly agonized the eye to look at it.”

It’s comforting to see Pepe riding high on Dan’s life jacket.

There’s green water in the distance. We head toward it instinctively, kicking up ash like postapocalyptic pilgrims.

From the moment it tumbles out of the crater, the 38-mile Aniakchak River runs south toward the Pacific as if it’s late for dinner.

We hoof across otherworldly plains of dust staged with small rocks, where I’m pretty sure NASA faked the Mars rover landing.