Instead of a backpack I carry my hunting gear in a Tactical Tat'r 2 turkey vest. The seat comes off easily for deer hunting. The vest provides separate pockets for all of the essentials (binocs, camera, range finder, etc). Also the large right hand front pocket works well for carrying my pistol. The game vest on the back works for rope and/or extra layers of clothes.
I typically treat it like a pack and take it off before climbing and then once I’m settled in I pull it up and hang it from a hook in the tree. The nice thing is it hangs around the tree trunk and doesn’t create a large profile in the tree like a pack.