I was, however, able to modify them to a single night only without penalty. This hybrid plan actually works out better than either of the other two options.
Tomorrow I'll drive down and see the first day of the event in a recon mode - see how people are dressed, see if the parking lot can take the van, and basically scope things out, and then drive home.
Friday I'll go back down, and Friday night only, stay in the hotel. Saturday morning I'll check out. If I can get the Van in there I'll just stay in the parking lot on saturday night, and I should be OK through Sunday. If not I'll just come home, 3 days of this should be enough for the first year.