I have a 2001 Roadtrek 190 Popular with the continental spare tire kit. Total length is just under 20'.
I ordered a Classic Industries cover (up to 20') from Amazon and am very pleased with the unit and its performance during this New England winter.
Here is the link:
This cover is well designed. It has 4 straps that go under the RV from side to side. A small bag, which you can fill with a stone, is included so you can throw the strap under the RV so it makes it to the other side. There is 1 strap in the front and 2 straps in the back that go across the van. Once cinched down, wind flap is minimal. There are zippered panels with long pull cords to gain access to the side door, rear door and side doors. Once the zipper is open, the panel can be rolled and there is velcro strap to hold it open. There are also plastic rings high on the sides to attach guy lines if you want. I also like the fact that the top is white to reflect the heat.
Someone was thinking when they designed this cover. It is lightweight so it can be handled by one person. I use a 5' pole, (1" PVC pipe) to hold up the top and lift it to clear the roof obstacles. With practice, it can be done with one person.
I like the fact that it can be unzipped to get into the RV without removing the cover. The fabric is also treatable, (details on the Amazon site). For the money, it is well worth it.