I believe their is an order of hierarchy involved...
1.Guests staying on property
2.Annual passholders etc....
I don't know the exact logistics and even want to.
I know this question has been answered before if you want the complete "legal" order, you might do a search?
However I think the more important question to consider is, Do you want to be in a park that has closed because of reaching capacity??
I would imagine that time frame (of closing to additional guests) would be towards late morning/early afternoon and you would have had to sleep in or dawdle around to arrive that late.
I would try to arrive at MK early and get on some rides before it got completely insane, and then hop over to another park in the afternoon that would hopefully be less crowded.
Just my 2 cents