Sailors & RVers have a common enemy. Chafe. That little movement may not seem like much but when it happens tens of thousands of times something is going to wear.
I used to cover my 32' boat for winter storage. There were many more sharp corners & weird shapes on that boat than any RV, which is basically a box.
Tape folded terry towel over sharp corners. Tie the corners down. Around the sides add water filled bottles to help keep tension. The bottles should be hanging off the ground. The size of the bottles used will depend first of all on the strength of the cover grommets, the amount of wind where stored & frequency of checking on the unit.