I lived and worked out for many years at low altitudes like yours. Running/jogging seemed to help and walking up and down any sort of slope with a pack seemed to help. So, I'd concentrate on that for conditioning.
But, the best way to get used to altitude is to live there for as long as you can prior to hunting. Even a couple of days between 6000-8000 ft. helps alot. BTW, working out after you get there doesn't seem to do much unless you have been there for a week or so. E
