If I come in after 10pm can I get through the gate or is there a place to park and walk through?

Unless something has changed recently they only close the gate when the campground is closed.

We recently camped here at the spot closest to the entrance, we never noticed the gate being closed (can't speak about the pavillion area with the covered area). There does seem to be some "unsanctioned" parking by the entrance should the gate be closed, but I don't think you'll have a problem.