We didn't think we would like a foam mattress either.
Original mattress in our TC was a queen 11" foam. It was way too soft and as you said hard to roll over on.
The wife wanted more storage so we put in a 6" extra firm full size foam from Walmart and we like it. I'm not sure if it's that it is only 6" or if it's the extra firm that helps.
We would buy another if we ever have to replace.
As WVbassmistress said, it's easy to get the new one in.
"I" had no problem getting the old one out, I got my boys to come over and do it. I knew we had kids for some reason.