ellie007, I have the exact same issue with my 25' 2004 Alumascape trailer. My wife disassembled the jack-knife sofa and added much more high quality foam. It is better but far from perfect. It's fine for sitting for up to an hour but if we are stuck inside on a rainy day it becomes miserable. Like your trailer, underneath my sofa is a box about 12" tall that contains the slideout mechanism. I have been looking for something like "openspaces" suggestion of a seat with no legs to be mounted directly on the slideout parts box. BTW, other than this one flaw my wife and I love our trailer. All our friends have much larger trailers and they can't get in the many remote parks we go to. Good luck!