I like the nice firm cushions in my Grandby - I never wake up with a backache.
My son, however, prefers soft and cuddly to sleep on. I removed the 4Wheel foam mattress. I replaced it with two layers. The first layer is a 1 1/2 in convoluted foam mattress from Wal-Mart. On top of that is a 2in feather mattress pad from Sierra Trading Post. I made a slipcover for the pads out of weather resistant Sherpa fabric. I found a matching Sherpa body pillow at WalMart. A comforter goes on top of the bedding and the roof comes down without issue.