We went there 9:30 or 10:00, don't remember, but it was before they closed and it was after Fantasmic. We had an ADR (this was May 2007), but we wouldn't have needed it -- the place was less than half full that late. We had awesome "grownup" shakes, with Bailey's and Kahlua Hope to stop in late again this September on our HS day.
Our young teens have never been to a drive-in. Is the atmosphere inside SciFi really like sitting in a drive-in movie? Will they be able to order from the kid's menu?
We have never been able to get in, even in "off times", but this was in September during free dining, so that is skewed somewhat. this time we are making ADR's to make sure we get to see that place for once!