Wade tapped me on the shoulder. “I’m not up for this,” he said. My heart sank. I knew it was the right call: he’d been under the weather for a few days. But we had trained so hard for Denali’s Cassin Ridge, and now, moments before dropping into the abyss, it seemed we were on the verge of tapping out.By then I was nearing the end of my first climbing trip to Alaska. My plan going in was an obvious choice for a Colorado cowboy looking for a wide-eyed wake-up call: acclimatize with a hot lap of the West Buttress…