You'll already have most what you need on you.
Flashlight (I assume, I carry a headlamp because I leave camp at dusk)
Fluid (water) & Snacks.
Only additional I'd carry is:
Mirrored or shiny object (for signal)
These are thinks I always carry when I hike and fish out west. I guess it depends on what type of hunting you'll be doing.
The altitude can be a killer. I run regularly in South Florida but being 3 ft elevation it takes a little bit to adjust. The better shape you're in the better the hunting experience will be.