MY FRIEND NATE CROSS was turning 40 and wanted to take a river trip. The months leading up to his birthday had been tough. After 15 years his dog had died. That was five years longer than he'd been married. For a few weeks, Nate had carried photos of Junction in his shirt pocket and showed them to bartenders and waiters and cashiers. He told me that when he added up all the miles he'd walked with that Lab, it was about the same distance as circumnavigating the globe.

We all needed a river trip. That's how we know each other: Nate and Adam and Ken and I had guided together for Outward Bound in Utah and West Virginia and Alaska and Baja. Now those days of living under tarps are five years behind us, and we all live in houses—which we actually own—in Missoula, Montana. Ken Miller is 38, and he and his wife just had their first daughter. Adam Duerk is 37, practices law, has twin boys, and might someday run for office. Neither of them had been on an overnight river trip since their kids were born.

So on a cloudy evening in June, after a day of thunderstorms that delayed our chartered six-seaters 12 hours in Kalispell and left us with a $300 bar tab, we and four other friends landed on a strip of grass in the thick forest headwaters of the Middle Fork of the Flathead River, in Montana's Bob Marshall Wilderness. During those long northern summer days, it stayed light until 10 p.m., and the pyramid peaks in the distance still held gulches of unmelted snow. The river was shallow and cold, gurgling between cobble islands before gathering in a channel and slipping past.

We were about to launch on one of the last real wilderness rivers in the lower 48. The only way in is by bush plane or horseback, and the way out is over 23 miles of Class IV whitewater through the habitat of grizzlies, moose, bald eagles, and mountain goats. But we were prepared. Between the eight of us, we'd racked up 70 seasons of guiding experience—50 among Nate, Adam, Ken, and me alone—and on top of that we had two rafts, four kayaks, six cases of beer, seven bottles of small-batch bourbon, one pistol-grip shotgun, and a gorilla suit.

As for me, the youngest, having neither wife nor child, I didn't have a good excuse for not getting out much. I'd lived the past two years on the East Coast and, since moving to Missoula in 2005, had been sequestered in my house writing a novel. Although the town is teeming with fresh-faced, cheerful outdoor types, I'd fallen instead for the token city girl—she'd never been on a raft or a snowboard or a mountain bike and frankly didn't see what the big deal was. She met my declaration of love with one part amusement and one part detachment, lit a cigarette, and said, "What am I supposed to do with that?"

So I wrapped my heart in a waterproof bag. Forget all that crap about finding yourself, communing with nature, and camaraderie with the boys: I fled to the wilderness this time, as always, to escape the anxiety and tedium and heartbreak of trying to live like a normal person.