Some years ago I built from scratch a bow arch shed to store a Casita trailer in. I used a white 6 mil greenhouse plastic film that held up very well...for years. The shed was under a pine tree, and the cones would drop from on high and pinhole puncture the film, but the original layer is still on....13 or so years later. Tough stuff. A patch of repair tape sealed the pinholes.
Here's one link to the film.
https://farmplasticsupply.com/6mil-o...d36e2a0e82c4ab
They say a 4 year lifespan, mine is running on 13 years. It is sheltered from the sun, being under two 80 foot tall trees and squeezed next to a 6' tall wood fence and garage, which likely greatly extended it's life. Sold the house and moved a couple of years ago, and it's all still standing.
This is a polyethylene film; same plastic as a milk jug. A slippery film; ice is no problem.
I also wrecked a car cover with frozen water on it, removing it. Those covers are 3 ply laminates, good dry, but shred with winter ice & removal. Same materials as a trailer cover.
Pic of bow arch shed included. 6 mil film on sidewalls only. Ends were sheathed with white poly tarp, and not nearly as UV durable as the film.
with
A trailer could be wrapped with this film and provide reasonable UV protection and be water protected.