We stopped at Cave Point County Park while we were visiting Door County, and we really enjoyed it. There's a playground and great picnic areas. We loved checking out the view of all of the rocks below from where the water has shaped them over the years. Our kids were pretty small at the time, but they were still very impressed with it. Door County is a fabulous place to visit with your family - so many fun little places to visit - and don't forget to stop for some cheese curds!
If you want to see a beautiful overlook and not spend money going to a State park in Door County, be sure to visit this county park north of the Whitefish Dunes State park. Our 2 year old son loved the hike and I was pregnant with #2. It was a relaxing walk through the woods along the lake. There are trails across from the lake, too.