I used to go there all the time when I was a kid, loved it then and I still do. the Hartshorns were such a giving family. I think if your ever in short hills it should be on your list of things to do.
It was a bad weather day but they have a bird watching room,you can sit with book and watch for birds.Will go back in better weather.
Very small but also very peaceful and quiet. Good place to simply get away from life for a few minutes.