I don't know about Dutch Wonderland, but Hershey Highmeadows is a nice campground. The campground itself is very nice, but there is a freight train very close. First time we stayed at the CG, the train did bother me, but only me the wife and kids were fine. Last time, we had no issues with the train noise (left the A/C on which covered the noise completely).
If your intent is to spend some time at Hershey Park, you really can't beat Highmeadows. They have regular bus service to / from the park for free, which worked out very well for us. You also get into the park a little earlier than the general public with access to some (not all) of the good rides. When we were there, there was the possibility of very bad thunderstorms. The park management came around informing every camper of the emergency location with provisions for your pets. While we didn't need to take shelter, it sure was nice knowing exactly what and where we needed to go for shelter should we need it.
We're going to Hershey again in April for an event at the stadium, and will be staying at Highmeadows, it will be our 3rd time there.