i'm in a casita
which shares the same dismal seating situation at the dinette. i camp host a few times a year and each time always involves inclement weather forcing a lot of seat time inside. the cushions provided form a 90 degree angle which is not comfortable for seating. my first solution was to build a frame for the oem cushions. this was an improvement as it raised the front of the seat cushion and moved the back cushion forward...kinda like a real chair.
turned out it still wasn't comfy enough for these old bones. then, a fellow camper told me about these. they're sold as "event seats", they fold in half and have backpack straps so you can get them easily to & from the stadium (or whatever). man! these things are the cat's meow...very cushioned and the back angle adjusts. they're pricey but i managed to get the west marine guys to give me half off the pair because they were "shopworn" (dusty).
after several 2-3 week trips and a 1 month host gig my seat search has ended.