Being from the Midwest, elevation is a killer and impossible to over train for. I have been to Montana the last 2 years, and have been in good to pretty good shape heading into the hunt. Running 8 miles, lifting, 50 lb pack hikes & 50 mile bike rides. The key to training is doing long workouts to build endurance. 2 Hour hikes and 2 hour bike rides are a big help. I think I am going to add ankle weights to my hikes. If my legs are lighter than when I trained, it should be less work for my body so therefore less oxygen needed.