Because of the high-altitude conditions, we're advised to take it easy and not work out for the first couple of weeks here.
Along with my daily 3-4 block trudge to and from the "summer camp" where I'm staying, I've started walking back from the drill camp each day (after catching a ride there on the local mass transit system, which is an on-call shuttle van.) It's a bit less than a mile from the station.
Next week, I'm going to start walking there and back. The week after, I'll add a 20 minute elliptical session and slowly scale that up during my time here.
I'm hoping that by the time I leave the ice, I'll have the lungs of a Kenyan!