That's a window onto a plateful of problems I didn't know you had.
The local VW swaps are on 1 June and 16 June. My favorite, times past, was the Porsche-VW swap in Amity, OR. I missed the last one last year. That's where i saw the Porsche 4-cam engine on a stand and the 1954 Type II riight-hand drive 23-window bus in showroom new condition (it was there 2 years). No 23-window bus you've ever seen, restored or no, prepares you for the upholstery those had from the factory. The proprietor, Gary Emory has progressed from Outlaw 356s to flat-head Ford 4-bangers.
The only Summer-zing I have left to do is mosquito netting, but I have a month or so to get to it.
What I'd like to do is lay a rectangular pipe frame 4x24' on the roof of the trailer and fill it with 2-3" of foam insulation. Then pile blackened scrap metal on that and cover it all with corrugated greenhouse glazing. Fan[s] in the roof vents, run at night in the summer and during the day in the winter.