Well just WOW... besides welcome I'm not really sure what to say. If the jalousie window in the door is operational you may just need glass and other minor items. Rear window could just need total refurb which is a real pain but doable, several good articles here on forums about these windows (about 1960
ish to 1965). Check out Vintage Trailer Supply for parts and seals. New tempered glass at your local glass shop, 1/8 inch thickness. Side windows look like well the whole side looks to be pretty damaged, I would start by excavating the windows and frames to see exactly what your dealing with, could be a lot of major repair work to the whole side of the trailer. A wider angle shot would be interesting. Every now and then complete windows pop up. I think Vintage offers the extrusion for the glass frame itself but I fear that the actual body frames could be quite damaged.
You have an interesting project on your hands...
Good luck, Mark D