I've used poly tarps to cover my camper, and they've worked pretty well. I usually go for a heavy-duty, UV-resistant tarp to make sure it lasts longer. The key is to secure it tightly to prevent flapping and rubbing that can cause wear. Using bungees...
I’ve heard of LIV Trailers and they seem to be generating some buzz lately. They are relatively new in the market but have been receiving positive feedback from those who have seen or used them.