I bought a cover for my trailer but I hardly ever use it. When the trailer is stored in my garage I find it's easier and better to just use a old bed spread to cover the trailer. The bed spread goes on and off easier and breaths better than a cover, and because the bed spread is kind of thick and padded it offers better protection to the paint if something was to accidentally fall on the trailer.
When I travel and stay at campgrounds, I do take my trailer cover with me, but rarely use it because the trailer is usually dirty from traveling and I don't want to put a cover on the trailer over the road grime, and I use the trailer for storage anyways and have to get in it alot, so a cover on the trailer just is a pain.
I guess, I wasted my money on my trailer cover.
Here is a link to a company that makes custom trailer covers if there isn't one already make to fit the Time Out Dart trailer.