Replacement depends on how old your RV is and if you like your current mattress so the answer? It depends.......
We replaced our leaking sleep-number bed with a Tuft and Needle Queen mattress ($600) Fits great. When I removed the whole thing I noticed mold inside the hoses, so I think it was a good time to let it go. Be aware that some RVs have a "RV queen size" that is actually smaller then the standard 80x60 inch so don't forget to measure!