We removed the Ideal-Rest mattress in our 2017 Adventurer about 2-yrs ago.
We purchased one of the many “bed in a box” foam mattresses sold online, such as Casper, Purple, etc.we bought a “Lessa” California King.
Lots of folks worry that the bed tilt when retracting the bed slide will somehow ruin these mattresses when stored folded for long periods of time. But we’ve not found this to be a problem at all. This subject has come up many times and folks worried about the bed tilt have phoned the mattress companies asking if the bed will still be warranted if stored folded over time. Of course, these companies have no idea and usually reply that the warranty does not cover such a use. But, again we’ve seen no problems from this.
The ideal-Rest King is an RV King sized mattress and is not the same size as a regular king. It’s 2” narrower than a regular king. We’ve found the California King is the correct width, but 2” longer than the RV King.
There is no way to accommodate any wider mattress in our RV. The side “tables” on either side of the mattress limit this width. But, there was a way to accommodate a 2” longer mattress in our RV. We removed the headboard on the wall behind the mattress and our Cali King Leesa fit perfectly.
We find the Leesa to be pretty firm but I’m sure that’s a result of the bed base being a sheet of plywood. Regardless it’s vastly better than the Ideal-Rest.
Here is the Leesa in place withe the headboard removed - it was super easy to remove it’s all one piece and mounted with 4-small screws, one in each corner.