I wouldn’t go smaller than a 3000 ci external frame pack with functional load lifters.
A 3000 ci pack will give you plenty of room for food, spotter, rain gear, cold weather gear, etc. but maybe I carry to much stuff.
External frame with functional load lifters will have the ability to lash the meat between the frame and the bag, load lifters will help pull the weight away from your shoulders and put it on your hips.
Whatever pack you get make sure you adjust it to fit you with a little weight in it.