Would the park ever let a party pay for a lock in inside the park? With all the rides open and employees to run them? It would cost a pretty penny, But it would be pretty sweet. Is this a delusional idea?
Yeah I don't think any GP would be able to do that unless, like Zachary said, they dumped cash all over their desks. But I did use to hear stories about Walt Disney doing overnight park visits with his family and of course how could we forget this:
I believe there was an option to rent a ride or buy ERT with pricing starting at $299.00 a ride I think. I know that companies have been able to rent portions of the park for certain things. For example, last year there was a concert held at the park but the park was just the venue, it had no part in organizing the event really. Those who organized the event ended up renting out France. IT is very likely, it won't be cheap and would probably be best if it was like for company meeting or something, or if you charged your guests like $25 each or something. But yes it is possible, however the expense would make it nearly impossible.
As far as a whole night with rides running and employees? I would find it highly unlikely. The Team Members are not allowed to work over 16 hours in a given day. This type of thing would make scheduling a nightmare. And there is no way you'd be able to have the entire park open for and entire night and into the next morning. That would go through three or four cycles of Team Members for the almost 48 hours. The only way this would happen is if the guests were to pay a HUGE (and I mean HUGE) pile of money to offset everything and pay for all of the poor Team Members to stay into the late/early hours. Yes, I know Disney did the 24 day, but they're equipped and used to doing this sort of thing.
I will say, though, SeaWorld parks (I'm not sure which ones, but I know definitely Orlando does this) do a summer camp thing with teens/kids and there are options to spend the night. But it's in a small area and nothing is open.
As far as scheduling goes, you must have at least 6 hours between each scheduled shift, and I would like to guess they typically have 1/3 of their employees not working on any given day, with the exception of predicted extreme high and extreme low attendance days. So I could imagine if they fully staffed everyone, it could be done. Also, I could see the park using the loop hole 16 hours in a day, the day ends at midnight. Therefore, they could work longer consecutively.
It's actually 14 hours in a 24 hour period, that's how they keep the loophole closed! Trust me, I was a truck driver for 8 years! When operating heavy machinery, which I believe includes roller coasters, especially since their are "civilian" lives in their hands.