I'm not sure where you will be doing your multiday self supports, but if your have trees available, then I'd suggest a hammock. Absolutely the best way to relax your back at the end of the day. I never hit the river without mine anymore (and I'm a rafter, who can also carry a real camp chair). You can lay in it or use it as a chair. A single hammock packs down to the size of a softball & doesn't weight very much. I learned about hammocks from the ultralight backpacking crowd. A lot of them use hammocks & ultralight tarps now instead of tents.
Trek Light single or Compact, or ENO single are good choices.