This will depend on how long you're going to be there, how much you'll be using it, and what size cards you use.
The first thing I would do is figure out how many hours a SD card will record. I would also be sure that all the SD cards are Class 10.
If I was going to be at all 4 parks I would use different SD cards for each. This would make editing a lot easier.
Once you figure this out it will give you a good idea on how many cards to take.