If they like water parks then yes, it is worth it for them to go. MI's waterpark is awesome and worth the price of admission itself!
The Mad Mouse is a coaster that they would probably like. They might be up for Woverine Wildcat, a smaller wooden coaster with lack of airtime. They could also do the two 'kiddie" coasters: Dipper & Zach's Zoomer. There is the usual flat rides such as scrambler, swings, swinging ship, and ferris wheel.