Hi, Yuppy,
In summer, leave the sail rigged and let dry. Naturally, you’ve used 303 Protectant (available from Autobarn) as an anti-UV aid, and naturally, you’ve applied it at the start of March and at the start of September.
In winter, de-rig the sail first thing, roll it into its bag, then stand the sail on its luff end to leak as much water as possible. After everything else is placed in the van, place the luff end of the sail into a
thick plastic bag (ex JB HiFi or Harris Scarfe), then fit the sail across the back of the van (or lengthways in the van) at an angle, so that water continues to drain into the plastic bag. At home, remove sail and drain/dry in your garage.
If you leave the wet sails in your van, the atmosphere will be salty and you can expect rust to form. You might consider fitting a Muller vent and a rotary vent available from this Dandenong outlet at very good prices:
www.uesint.com/ If you cut the metal roof, make sure you seal the cut metal edges to prevent rust.
I agree with Glynn Merritt re the rear step and SS screws. If you have a look at vans that are a number of years old, you’ll probably find they have rust on the rear step AND in the sliding door step. One drop of unfound salt water in these areas and you’re in trouble.
Hope this helps.