TP:
re: "I made supports for the jack-knife soft using 2" schedule 80 PVC and 2" to 4" schedule 80 PVC couplings. 2" PVC pipe is slotted to fit frame of the sofa. I have a 1/4" sheet of plywood the size of the table (fits under a dinette cushion) that I lay over the crack between the sofa and knocked down dinette. On top of that we put a throw."
I'd love to see photos illustrating that frame. I'm having troubles visualizing the application of the slotted PVC. Maybe I can cobble something suitable together. We did get a Coleman air mattress...while it was 'better' it really didn't serve out needs very well. Got the little 12V air pump, could have used that back about 50 years ago...