Making Foldable Beds more comfortable in Hybrid Trailers

I can't offer much advice. We simply throw an open sleeping bag on top. Seems to be enough for us, we both sleep like rocks. For now. We're well into our 50s so I imagine that at some point we may need something more.

Our old hybrid actually had a split mattress and it wasn't split down the middle, more like 60/40. So we had to get a topper just to keep one of us from sliding off the mattress.