An additional thought:

The pre-planning is critical, I think. And you need to include the others as well. Their fitness is critical; I've escorted friends who assured me they worked out regularly and strenuously, only to find out they played half an hour of racket ball once a week. How far and how rugged...everybody needs to be in on that discussion. Which in turn relates to whether to base camp or keep moving.  

Consider also the desireability of layover days rather than pushing on every day.

Tim