In this video of the Imua Bike Camper build I make the 2nd panel. They are one sheet of fiberglass reinforced with half rounds of PVC pipe. There will also be primer and 2 coats of paint on each side.
Nothing like that available on Kauai. I am going to put 3 layers of house paint on either side. The fiberglass panel is plenty strong I am just trying to thicken up the walls for a little sound protection. This trailer will not be hauled long distances as I live on a tiny little island with only one bike path. I will be giving it to a houseless person who will tow it somewhere and park it. This is why I am going 4 feet wide and not optimizing it for travel. Once I get the box assembled on the frame I will have a good idea about its rigidity and what additional reinforcement it may or may not need.
