Look past brochure photos at vertical gain per day, number of nights above 4,000 m, and whether rest days are built in or treated as optional. A “moderate” label on one route can feel harder than a “strenuous” label on another if the latter spreads altitude more gently.
Ask operators how many hours you move on longest days, what happens if a domestic flight is delayed, and whether your guide can split a tough stage if the group fatigues. Good answers reference hours, not just kilometres.