Hershey is great! We went last thursday and lines were 5-15 minutes depending on the ride. There is a water park there too which you could spend all day there if you wanted to. The rides go by height --check out their website. They have a ton to do and the crowds are very family oriented. Be sure to go into Chocolate World -- they have a free ride in there -- really cute for little kids and of course don't forget the chocolate!
We were looking at Dutch Wonderland (which we have been too), but then thought about Hershey Park. I have a 3 and 6 year old. Would there be much for their age at Hershey? We have never been.
I took my kids that young and had a blast, very family oriented. Don't miss the 3-D movie its awesome.