[KeithInUpstateNY]

RV mattresses are one of the most common complaints about rigs at all price points. "Josh the RV Nerd" (YouTube, Haylett RV) just did a video about them, and his explanation makes sense: people's sleep preferences are so different that no mattress is going to satisfy even the majority of people so manufacturers equip their units at the lowest price point possible, knowing that for occasional use most people will "get by" and that those who use their rigs more will replace the mattress with one that they have selected that meets their sleep needs.

As for the odd sizes, there are sheet sets available for the various RV sizes, both at places like Camping World and online at Amazon, Walmart, etc. Because they are not as popular you do pay a higher price for them.

Usually it is the length that has been shortened to fit the space available. Since I also wanted to replace my mattress, and I'm single, I replaced my RV queen 60x75 mattress with a standard 54x75 mattress that I could easily get sheets for, with the added benefit of having more room to move around the bed. RV Kings come in two lengths from what I've seen: 80 and 75. If your mattress is 80" long you could replace it with a standard 60" wide queen. If it is only 75" long you would have go all the way down to a 54"x75" standard full to get sheets that fit off the shelf.