Covers are not only expensive, rub the paint with the wind, kill motorhome owners who try to put them in the wind and make access restrictions.
On other hand lot of vehicle owners don't think what sunlight can do in 3 or 4 years and sometimes I cry seeing good vehicle with paint peeling off because owner choose to keep $70 worth of c**p in the garage and car sits on the driveway.
Coming to storage, once I kept my TT and boat at open storage at the lake.
The owner allow me to raise those tent garages for the season for $5 a month more.
The metal carport posted above would be the best, but also more complicated.
But don't forget to cover caps that can get UV.