I am a couple weeks away from 65, and am going on a solo backpack deer hunt in CO this Sept. So, if your body holds up you can still do it. I just completed a couple months of wilderness canoe guiding, and did make the move to bring a Helinox camp chair. I got the slightly heavier one as it was substantially sturdier and more comfortable than the 1# one. Mine is 1#9oz. It was an absolute plus for me on a canoe trip, but will have to see where my pack weight ends up at before considering bringing it on a backpack hunt.
I try to always camp near water, but do have a good supply stashed back at the truck. In past hunts, I have never gone back for water, but on a dry year it could be necessary. I don't care much for most of the freeze-dry products, so make up my own meals from common dry goods, but you have to ensure you cover the calorie, carb, protein,fat requirements. It's heavy, but peanut butter is well rounded and calorie dense, and a plastic jar will supplement your meals. Bring enough line to hang your food up an night and in your absence...no point in packing it all in just to feed the bears.