How many people are you going to have? I guess a bunch, since you have a van? I might suggest you just get a cab for the trip over and back, as we always have a tiny car and often have problems getting in there and getting a parking spot, unless we get there by about 9 am, as Elaine said.

that's going to be an issue several places with a van, finding a place to park. That's why I generally recommend for people to rent two small cars, versus a van. Generally cheaper for two small cars, or about the same price, and gives you more flexibility.