We experimented with a number of ideas and found that the best idea for us was:
1) a 2' memory foam topper which we rolled up and put on the sofa but it is lightweight. We have had this almost from day 1. It helped a lot but the mattress that came with the trailer was garbage, worse than a Futon.
2) we recently picked up a 4" foam mattress from Ikea. It has made a huge difference for sleeping. We have been struggling with how to store it because it is heavy and we have looked at a number of ideas for how to store it, but because it is so dense compared to the garbage that came with the trailer, it would not fold up and compress as small as the original bed with the tent end closed. Right now the best we have come up with is to fold it in half and then drag it down onto the floor between the dinette and sofa. It does use some floor space and it is a bit of work getting it back up when we setup again, but the improvement in our sleep is well worth the extra work and loss of space. With it and the 2" memory foam on top it is the size of a real queen size bed so sheets fit properly and there is no gap to worry about.
