Flew that exact camera/lens setup on this spot at around 9,000 ft in the Rockies. Not winter though luckily. But still had very uneven terrain, mud, rocks and such. Best advice I can offer for working at altitude is drink LOTS of water and get someone else to carry your sled back to one. That way your are not waisting precious energy when you are only breathing around 75% of the oxygen you get at sea level. The shot at :07 in was a nice trek up hill through low scrub. Around 6 takes. You bet I had a grip carry that sled back to the start.
Now that I think of it, I'm always operating at altitude. 5,280ft. minimum here in Denver. No wonder I'm so tired all the time. :rolleyes: