I am doing RV share for the weekend. How does that work? How do they get in there to set it up and nowhere to set it up? Or do they set something up with a campground? Or wait until we get there?

We had a trailer dropped off for Beyond Wonderland back in June. We made sure to communicate with the folks at the gate and they let us both through. The folks flagging us to our camping spots redirected him to the exit (they write a camping code on windshields). We got out of the car, explained what was happening and the staff eventually allowed him to drop off the trailer.

I'd Check their website, call their site office. Then schedule a spot ahead of time unless it's a first come first serve area?