I was in RC-South Zabul Providence in the Mountains at FB Baylough. 8,000 feet was the elevation of the FOB and we did dismounted patrols up to 14k feet ALL the time. It was way to rough for our trucks.
I suggest drinking LOTS of water and doing cardio on the FOB when u can. I think it's more important than raw strength at higher elevation. The first few times u do it start slow, if you are not use to it you might get dizzy or even sick.
I never went anywhere off the FOB in the fall/winter/spring without my fleece cap and warm gloves. When you are moving you don't need them but the second you stop things get pretty cold fast.
As for comforts, I lined the walls of my mud hut with those wool humanitarian aide blankets. (I'm human and I needed aide). I insulated the hell out of my shack and it helped a lot, the wind is your enemy. I also kept 1 pair of boots inside my sleeping bag (one layer out) when I slept so I didn't put on a pair of iceboots in the morning.
The survival stuff is all in the books that have been recommended and a lot of it is common sense. Knowledge is power. I just tossed in some of the things that I did