We had a memory foam mattress topper (3", I think) left over from our Class-B. That has been on the trailer Denver mattress since day one. We've slept in the trailer only a few nights so far and the mattress is acceptable/tolerable but almost too hard.
The jury is still out if the Denver mattress will need to be replaced or not. Next month will be a longer trip and we will decide after that.
Sherm & Terry w/rescues Steve (std Poodle) & Eydie (min Schnauzer)
2015 Jay Flight 27RLS (Camped: 102 nights 2015, 90 nights 2016)
2006 Ford F350 6.0 PSD, Lariat, 4WD, CC, LB, SRW, auto., Camper pkg.