when we needed a new mattress, there was(is?) a mattress factory over close in Jackson, TN. we went there, and they made up one especially to fit out MH. The salesman also owned an RV,so he knew exactly what we wanted. As our bed in that MH was in the center, he knew that we would be sitting on the bottom edge, and less often on the sides, so he built extra support on the bottom edge, and a bit more on the side. At the factory sales floor, we got to try our every style and firmness they sould make, and selected exactly what we wanted. Two days later, we went back over and his men installed it and removed the old one for us. And it still cost a lot less than store retail. So look around the local area, and on the internet for a mattress company in your area. Mattresses are expensive to ship, so many areas have local manufacturers.