I can strongly recommend what we bought. We use the existing mattress and added a "Perfect Harmony Mattress Topper - Short Queen" that we bought online at Camping World. My wife shopped and researched extensively and this is the best she could find. It's not cheap; you can spend a lot less buying something at Wally World, but A. they're not nearly as good, and B. good luck finding a "short queen" size. This fits perfect and having just returned from a 4-night trip, we both agree it works great. Neither of us are lightweight people either, and it supported us fine with no back aches. Here is the link: https://www.campingworld.com/shoppin...rt-queen/60993
. At $165 (today) plus $9 shipping, it's not cheap, but then again, I guess it is compared to the alternatives. "Cheap" is relative. When you consider that you're only using a mattress with no box spring, adding 4" more to it for $175 is a pretty good deal. Wife said she wouldn't mind if it were even thicker. We might consider someday adding another few inches of foam between the mattress and this topper (or perhaps just under the mattress), especially after both compress somewhat down the road, but for now, this is an excellent solution we can vouch for. (63 reviewers on Camping World give it 4/5 stars, so most of them seem to agree.) Hope this helps. By the way, we had trouble finding options for short queen sheets, too, and we bought a set of "Short Queen Sheets - Vanilla" on Camping World for $30-something. https://www.campingworld.com/shoppin...-vanilla/70928
. We're happy with these, too. I recommend washing them before using. There was a slight chemical odor the first night, likely from the dye or sizing. They also softened up a bit after the first washing. They're not the best quality sheets we've ever slept on, but they're nice and we can recommend them too.