Once you pay to go in, does it include all the exhibits? Or do you have to pay to go inside each one?l

All for one price, the only "second" cost is for parking...plan on a good 2.5-3 hrs...even as an adult, you will be entertained for that amount of time

Yes, everything is included

There is no other charge once your inside that I've ever noticed.

Yes. All exhibits included in the admission fee

Everything is included

It includes all the exhibits. If you go on the weekends, they also include a show tied into visiting exhibits