I have no high altitude hunting experience, but in a previous lifetime as a Scoutmaster, I did a bit of hiking on the Appalachian Trail. Although all training is important quads and back figure big in the muscular development area. Just as important is respiratory conditioning. Footwear is as big a consideration as the physical conditioning. Take care of your feet! Also, don't forget diet and hydration. Carry adequate emergency gear and review your first aid and navigation. As you well know, common sense is needed in the training program as well as the field experience. Sorry if I come across too simplistically, but when I dealt with this sort of thing, I was working with Boy Scouts.