Is there a re-entry fee for people who leave the park and come back?

You get a ticket to display on your windshield. If you call the park they are the ones who can answer. They are very helpful.

There is a yearly pass to stick on the window you pay for once. Then there is a daily pass you pay at the toll gate for a new day.

Only if you lose the pass somehow. Leave it in the car. It's dated.

Not if it's on the same day