For camping maybe think about a hammock.
If trees are available it should be a viable option. tarp, hammock, insulation, flash light, packable alcohol stove for coffee would all fit in one side along with tire pump/repair. leaves the other side for the clothes.
I have a trunk I'm fond of using so that's added space.
I have a 10 day trip coming up (Laconia)... I might have to do a pre-pack and overnight someplace to make sure I have what I need.
I don't see why you couldn't do a change of clothes, wallet, cell phone, maps and head for the desired pie spots, seems like that's really all you "need".