Where do you live, and where are you going through?
Hershey is just okay, not a lot of rides IMHO. The factory is okay.
But if you're going through VA, for a lot of BIG rides go to King's Dominion, right off 95 North of Richmond. If you have a little more time and a better family atmosphere go to Busch Garden in Williamsburg. They have lots of rides, a water country park down the road, and more family things to do at the park.