The 2″ Gel Swirl Memory Foam Topper from DreamFoam Bedding is an excellent option. It comes in tons of sizes, including short queen, which you might find in an RV.
This mattress topper is two inches thick, so it can provide enough support without being too thick. The mattress topper uses a soft, elastic memory foam to make any mattress more comfortable.
It comes rolled up, so you will have to give it a day or so to unroll and expand. Once it does expand, you’ll have a high-quality, U.S.-certified foam topper.
One customer said the mattress topper was better than they expected. However, other customers say the topper is regular foam, not memory foam.