Most of the packs that long distance hikers use have a big mesh pocket on the front, a couple of large side pockets, and usually a pair of hip belt pockets -- everything I need during the day fits in those pockets with the possible exception of lunch. Snacks go in my left hip belt pocket; gloves, hat, hand sanitizer go in the right; water bottle in each side pocket; the mesh front pocket holds my rain shell, map, rain cover, warm layer when I take it off, TP, etc.
The ULA has a rigid internal frame. The Circuit would be reasonable choice -- there are hundreds of them on the trail every year. We have owned three of them. I recently replaced mine with a Zpacks Arc Haul, which is similar but probably a little trickier to use. But it saves me about 12 ounces, which is significant when talking about packs this light.
You're getting good advice here. That military pack you own is terrific, but empty it weighs almost twice as much as my two person tent, sleeping bag, pack, and pad combined (seriously). Unless you're planning on carrying 50 or 70 or 100 pounds, it's way overkill.
Good luck with the planning and the hike.