We are planning on coming Monday, but the forecast calls for rain. If it rains on us can we get a "rain check" and come another day?

No

They do offer rain checks contingent upon weather for the remainder of the day.  This is evaluated on a case to case basis.  Also, they do have a second day free with most types of daily admissions. Second day free is not available with complimentary or school group tickets.  See Guest Services if you wish to inquire about a rain check.

Nope, there are plenty of overhangs for rain protection, but lightning is definitely a ride stopper.