The RV king mattress are not a true king long, but more like a queen in length.. A mattress can easily be custom made for you, but sheets would have to be custom too. If you have a Euro spring under the mattress, it will have to go and replaced by plywood to accommodate the wider mattress.
Elliott & Vicky, and Sadie the GSD copilot
2014 36RE, Onan, Titan disc brakes, 17.5 inch Sailun H tires, lots of other options
2013 RAM 3500 CC, LB, DRW, Cummins, AISIN, 4x4