Pretty much what everyone else said. Get in as good of shape as you possibly can, it's funny how a pair of boots that you can walk miles in at 5,000 ft can feel like lead weights at 8-10k feet. It will be hard, even if you had a week before to do it, to get acclimated to the elevation. One thing that will help is to keep yourself hydrated. Avoid caffinated drinks and alcohol or be prepared for the headaches that will come.
Elk are big animals and at that time of year, it's going to be hot enough to ruin meat if they're not cared for properly and quickly. Take some game bags to help protect from flies too.