3/4 length Ridgerest
Tent floor or, if in a tarp, plastic poncho groundcloth, or, in dry warm weather sometimes, just the Ridgerest
Pack under feet (for slight foot elevation as well as insulation/ground protection)
I am 56 and thus have every right to be creaky and need more padding, but since I sleep on an old packed-down futon at home, lack of padding while camping doesn't make much difference. It just depends on what you are used to.