I keep my '48 Chevy 1/2 ton truck in an unheated pole barn during the long Michigan winter. I place a soft dust cover over the truck, and then have it completely enclosed (zipped) in a CarJacket.

http://www.carbag.com

It uses a heavy-duty zipper and keeps the varmits out. I have been very happy with it.

LUKE

1948 Chevy 1/2-Ton 5-Window Deluxe
More pix in the Bolt Bucket