For your uses, I would avoid U/L packs, they are not much use, IMHO. I totally concur with PapaRon and I would suggest a Mystery Ranch Glacier-4200 cu, in- as being ideal for your uses. I like to add Fliptop Boxes on each side of my MR waistbelt for keys, wallet, multitool and flashlight plus a few bandaids i/c of blisters.

I am using five different MR packs at present, have had two others from Dana Gleason, one is over 30 yrs. old and still good, after mega use and these are the best production packs I have ever seen. I have had about everything out there and sold gear for my living, MR is awesome.

For light loads in really WET weather, the NAOS type packs from Arcteryx are neat, but, they lack any outer pockets and daisy chains, they are really designed for rock climbing, IMHO. They also will not come close to a MR for packing serious weight in comfort and MR packs fit big folks really well.