I am prograzing for the most part but i also think that the winter range of our wildlife should be taken into account. I know of some areas that are grazed heavily by cows all summer, then the deer move down to winter range and nothing is left for them to eat. Another reason these wild horses...
Killed my 2 doe antelope this year with my 6mm Creedmoor shooting the 105 Berger Hydrids. Built the gun for a LR Coyote Rig and it did the job just fine.
Altitude sickness is a real thing, and it effects are different on each person. There are pills out there that are said to really help. Cheap insurance vs a ruined hunt.
Dont go too high too fast. Lingering a day a 8K, one at 9K, and one at 10K will help you a lot.
All you can do is get in the best possible shape and roll with it. Id try and concentrate on lungs and circulation, and do HIIT exercises quite a bit. Hiking with a weighted pack will help.
Not sure what altitude you will be hunting, but arriving early and letting your body acclimate with also...