we have a 4-inch memory foam topper on our bed (this year's tax refund . . . oh, yeah ;-) and it's nice . . . quite nice. Basically, for both of us (Cody's got a bad lumbar Army injury, lots of nerve damage, and costochondritis) softer is better.
and standing in line - no. Just no. Drive-through if at ALL possible (you can even get gas station attendants to fill your tank if you put up your parking tag and honk twice. If they're paying atention, that is) and standing in line just . . . avoid it. If you anticipate standing in line, TAKE YOUR CANE or wheelchair or walker, you'll get extra sympathy, may be able to cut in line, and if not, you can still lean on it and rest. I usually also wear shorts or show lots of cleavage. It helps a LOT with standing in line. *wink*