I have hunted at 13k ft in CO for the elusive Muley. I have also been fortunate enough to haul out a big one.It's a dang tough hunt, however you don't have to be an ironman to do it. I'm in good shape but not excellent shape. The key ingredient is take it slow. It aint a dang race. Pace yourself and be mentally tough. Take horses if you got them, and a freind who will tend them while your out hunting.Horses can, in every timberline area I have hunted, put you into core hunting areas. You'll still need to hike, but at least you won't empty the tank on your way in.I'd also look at drop camps.Good Luck.These hunts can be the most rewarding hunts anywhere.