The registration is closed at 11, but the office is open at 8 am. And there's Lots of dry camping. As Heather said just come into the gravel lot by the restaurant and sleep till morning
Probably not.
You can come in at 3 am but the spot you pick may have a reservation on it, so be prepared to move.
There won't be anybody at the guard shack and you can turn left into a big gravel parking lot. You'll be fine they're until morning
I believe you can just call and ask
Thanks! Your answer is awaiting moderation.