Does anyone know about campground availability?

We have a 27-foot Class "C" motor home which we would probably be bringing. Do they allow such rigs to park at the Museum during the festival, or do we have to park miles away and be bussed in? The last time we were there we had plenty of room to park the rig in the far lot, but that was not during a festival! We don't need hookups as we are completely self - contained for upwards of 3 days with just the 2 of us.

I doubt they would let us overnight in the lot even if we do get to park there, but having a campground within a reasonable distance would be nice.