I have been covering the trailer with a tarp until I get the outside finished and noted a bit of condensation on inside of the tarp. I looked at fabric carports, but couldn't find one with good ratings and tall enough for my build. I thought about a "breathable" RV cover, but they look like they have a million straps and would be a pain to do/undo every time I get a few hours to work on the trailer (My build has been done stealing time where I can - like most of the non-retired folks here.)
I finally came up with what I thought was a good solution - put two boards cross-wise hanging about 3 inches off the sides of the roof, with boards running the length of the trailer roof at their ends. Then put the tarp on that and run the roof fan to circulate air under the tarp and down the sides of the trailer. I "installed" this set-up one evening this week when I got home from work. I am not accustomed to the recent heat and humidity, working in AC all day. I got a little loopy from the heat and came inside for a while. While I was napping on the couch, the boys were kind enough to go out and lay the tarp over my set-up and secure the ends on the ground. Oh, with the increased height and width, I needed a second tarp, since the old one was barely wide enough to cover the bottom of the walls where the roof is highest. Before bed that night, I went out and inspected the boys work, focusing on the quality of the securing the bottom of the tarps at the ground.
Last couple of days, I checked each morning _NO CONDENSATION! I was feeling pretty smug - the roof is dry, the condensation problem taken care of. Now as soon as I get a day off with suitable weather, I can glue down the roof and start waterproofing with epoxy and paint.
I went out this morning - rain in the forecast, so I planned to work on bed framing and cabinets. It had rained last night and when I did my routine check for condensation, there was A LOT of water on the rear (lower) part of the plywood I have laying over the spars and insulation in the ceiling.
Figured out what I overlooked when I checked the boy's work? They had overlapped the rear tarp on top of the front one (roof slopes front to back) so that rain ran right underneath. I fixed it and have got it drying out, but won't be sealing any wall/roof cavities for a while. Guess I'll get more done finishing out the inside!