I put a King Radius sleep number bed in my TT. I now sleep as well as I do at home. I found it on sale at Camping World last spring and got it for $800 less than regular price. They have a short queen for RV's.
I put a full home queen in our Voltage and took out the cheap backbreaking factory mattress. We both sleep very well now.. If I were to buy another I would get a Staava mattress... much cheaper than store bought and very well made..They have a 100 dollar shipping return policy. You do nothing else if you are dissatisfied with the mattress for any reason. We have the King version of it in our home. It's great sleeping.
We purchased a topper ...' 2" lucid five zone memory foam mattress topper from amazon. We will see how this works
We have a king size memory foam mattress (came with the RV as an upgrade) AND we purchased a high quality 2" topper (weighs 30 pounds). Really sleeps nicely. Problem is that the fitted sheets don't fit exactly right since we only have about 6" total of mattress and topper. I did that RV Tip of putting self sticking 12x12 flooring under the mattress and it makes making the bed a bit easier since it slides now.