That would be a slow process. Probably take 10 to 12 hours to blast a truck bed. Sandblasting is basiclay an open air line, takes A LOT of compressor to keep up. Would also be tough on that compressor, it would run constantly.
I have a diesel 100cfm compressor with a 150lb media tank. Would take 2-3 hours to do a truck bed, enculding time to refill the media and then blasting time. Just thought it would provide some perspective.