Lotsof excellent ideas here. I use a hammock whenever possible as I find it the most comfortable by far. I frequently sleep in the hammock at home Whatever you choose, try it at home, and try the different variations there before going to the trail. That way you will know a system that works before your get out. Some years ago while suffering from an ulcer, I "learned" to sleep on my back. This proved beneficial when camping, as on your back, there are fewer and lesser pressure points to the ground or pad. Becayse of an arthritic lower back, I do need, however, to elevate my head, so pillow is a requirement. There are plenty of inflatables which weigh little, and the platy idea above is excellent. Less need in a hammock,just a sack stuffed with clothes is sufficient. finally, to repeat, try it at home first. Same applies to a new stove, new shelter, GPS or whatever. On the trail in a thunderstorm is not the time to begin learning.