You might try the Budge brand of cover I found at WallMart. Unfortunately the largest stock universal size didn't quite cover my '53 Chevy 1 ton w/ 9 foot bed! The cheapest flavour is grey soft and doesn't seem a good value, more short term or a dust cover. If available in the truck cover the Tyvek, same as HouseWrap, is double the money but seems worth it. (I have these on my Opel GT parts car and project respectively. Another weather shelter also from WallMart is the poorman's quonset hut: a steel tube frame with white tarp roof and sides ( no ends) 10 x 10 x 20 feet I think. Some carcover makers have the pattern for the stepside I'll look for the literature I picked up at Carlisle and email the info to you.

EightLughead
1953 Chevy (covered in Blue Tarp found on I-95), last registered 1983!