Sounds like you may be looking for more support to the platform, but I can offer my two cents on the mattress itself. I read a lot of reviews and went with the highly rated 4" Serta memory foam and pillow top combo and its unreal. We love it......we just placed it over the mattress that came with the camper. As a matter of fact, we prefer it over our nice mattress in our house!
Couple of things to mention ....we bought it at Kohls and used a promo code for a great deal. King size for about $150 after discounts. (I've also seen it at Sam's club.) Tip - we used an electric knife to trim it for a perfect fit. The electric knife on the foam was like a hot knife on butter!!
Sent from my iPhone using Tapatalk