Does it ever fill up? Do cars get turned away?

Yes. You need to get there early. Most people seem to bring things to play and do while they wait for dark.

I went at 830.. Still open spots

Yes. And they ooen at 6:30 but if the line gets too long they ooen earlier like 5:30.

Yes, they do fill up

Best to show up around 4 or 5

yes they sell out and cars get sent away