I spend alot of time with a pack on my back, and at this point i only buy from three different companies. Kifaru, Eberlestock and Mystery ranch. Between the military and my own back packing ive developed some pretty big biases and preferences. I even back-pack to and from the grocery store with all my groceries in one bag (eberlestock dragonfly, monsterously big pack) so seeing as how i go about 2 miles every week with a pack that can weigh 100 pounds (seltzer water is heavy) i think i know a thing or two about what makes a good pack.
Each of the packs has a speacialty
Eberlestock: back scabbards that make it easy to carry a long arm, also a bit cheaper.
Kifaru: Toughest packs on planet earth.
MR: Comfortable packs that have unique designs that enhance functionality such as their unique tri-zip
i think youd do well with a mid sized pack, i reccomend the eberlestock half track. I carried one in afghanistan threw it in the back of trucks threw it on the ground kicked it around and abused it its ruggedly reliable and you can make it smaller by cinching down the side pockets. the main compartment can be stuffed to the brim and then stepped on essentially overstuffing it in the same manner as a top loader but it opens up length wise so you can easily access stuff, its hydration and radio compatible. it's comfortable over long distances and its modified easily by the wearer so that you can fit the pack more comfortable to your own dimensions. the top compartment is just big enough to hold your go to items some food extra rounds etc and the front flap has a pocket that can accomodate some oddly shaped items.
For 200 bucks its one hell of a pack than can do about anything you want, 3000 cubic inches can be alot if utilized wisely, and they dont even take into account that you cna really overstuff this pack, you can fit a tent in one of the side pockets, and then put your sleeping bag on bottom or top and then have the other side for a camelback and fill the main compartment with all the supplies youd need for days out in the woods.
If you want to go bigger or smaller and carrying a gun or rock solid toughness isnt your prime concern id definatley go wit h a mystery ranch trizip or a mystery ranch NICE pack for smaller and larger respectivley.
These might not be the cheapest options out there, but you get what you pay for. whatever you do get a pack with a real waist belt. if your not big into backpacking you dont realize this but the ability to take the weight off your shoulders and put it onto your hips is invaluable and you can then juggle the weight by loosening and then tightening the shoulder straps whenever you want to give a part of your anatomy a rest.
The biggest thing is to get out there and do it.
