[inghamm]

For our back bed we did this:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

currently unavailable. Ours was the first review. It's not as soft as our home bed, but softer than the stock mattress.
"This has worked well in our trailer. Right size, not too firm, not too soft, not too heavy. I like the idea of the gel, because the memory foam is famous for retaining heat. It is pretty good eliminating motion transfer as well."

For our front bed we just put this up there:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

It's a combination of air mattress and memory foam. Nobody has actually spent the night on it yet, but it seems like it might work well.