Hi--the hubs and I bought a secondhand pup from friends of ours a couple of years ago. It's about 20 years old, not in perfect condition, but suits our needs. However, we are ready to put a memory foam topper at least on our bed, because we're tired of feeling the plywood under our matress with our hip bones! Do we need to find a vendor that specializes in camper mattresses, or can we get a traditional mattress topper? Or does it not matter, so long as the measurements are correct? Where is your favorite place to get your toppers? Thanks!