Thanks for your feedback Fogrider and pdedes. My thought was strength training, arms and legs but especially core muscles. I thought the running and swimming would help build stamina. He's done 60-100 miles before, just not every day and not at elevation. It wasn't sure how the cross training would translate to such a different environment.

Looks like we'll be scoping out hilly roads this winter too. Good idea. Nothing like a lot repetitious back and forth on the bigger hills.