The original design was going to be a fixed wall between the sleeping area and the galley in the rear. I've put off building it since we are still having to take the mattress out to tinker with different things and ultimately we ended up really enjoying the open air. Built a frame and my MIL helped out sewing a screen with zippers, velcro on the edges. Turned out pretty well and now we can keep the back doors open the whole day.
Speaking of back cargo doors, I replaced the OSB with some plastic shower wall. It ended up being way to flimsy and seems to bow in the sun. Any ideas on a better product to use? To see the edges I used some white gorilla tape that isnt sticking as well as I'd hoped so I'm open to suggestions, just needs to be waterproof and hopefully light. Here is a picture of one door, although none of the issues show up in the picture: