You should consider a top cap on your van as you can find that your windows will get scatched if you fail to clean them. Any grit on the van needs to be washed off before covering it. The top of the van can give problems to the cover if you have a flue or tv antenna and will need a wrapping of foam so as not to damage the cover.
When you remove the cover go out and enjoy yourself and if you manage to create a convoy you should pull over and let them pass as I do. The drive to the campsite is part of the holiday and should not be rushed.
Never used a cover when we had a caravan. Had one for more than 35 years (not the same one) and considered a cover too dangerous for the health of the van. Just used a quality wash and wax additive to bucket of water and plenty of water to rinse off, and my vans were always in pristine condition, in spite of living in the middle of the area containing the 3 largest coal burning power stations in the land. Tried a farmers barn one winter - never again - got mice in the van.
The best storage place is a high carport, so that the top is covered but with plenty of ventilation.
dont but a pro tec cover what a waste of money the quality is rubbish" had mine for 6 months and it ripped from the back to the front,phoned pro tec they didnt want to know ( act of god )lucky for us the mother in law done a great repair job only for it to rip for a second time this winter in a diffrent place, so beware
If you do get a cover and tie it down, make sure it doesn't rub against the windows. I had one once and when it came to be uncovered in the following spring, the window "glass" was scratched to h**l and back. It took many hours of patient buffing with T Cut to try and restore them.