The problem with using a cover is that the trailer must be washed prior to putting the cover on. Otherwise, the cover will be rubbing the dirt into the trailer. We park our trailer at home, so it's no big deal to wash it and then cover it, but seems like that would be a major hassle in a storage lot.
Quads are for people who can't ride two-wheelers... KTM 200EXC KDX220 Auto-Clutch KDX220 KX100 CRF150 CRF150
If you plan on storing the trailer in the desert, do not even bother. With the violent uv sunrays, they break a cover down extremely easy. They only last a few weeks in the desert. With the money you spend, and will continue to spend replacing covers, you are better off spending the money on getting the trailer detailed and a nice coat of wax put on it.