p.2 #1 · Camera bag for a long and multi-days hike
Sounds like you're doing the smart thing on the hike and bringing limited gear, in which case I vote for inserts inside your regular backpack. I can personally vouch for the mountainsmith inserts referenced,and I think Tenba makes similar stuff. If you want to carry more gear in your regular backpack, and don't need superfast access to the photo gear, the small F-stop ICU's would work fine as well as they have sufficient padding that is not over the top in bulk or weight.
If you want to shoot as you are hiking, some optech pro loops and quick releases hanging off the D-rings of your backpack shoulder straps are a comforable and economical way to go, with the added benefit of shifting the weight of the camera onto your backpack straps.