When I was young, this part of the park had a play area for little kids. Now it is just an empty area with frences and a building. It is a nice, serene area of the park, where you can view many types of birds (seen while placing cache: cranes, parakeets, seagulls, and these huge metal ones). I also seen fish pop up in the water. Enjoy the area, despite it going to ruin.
The park is open from sunrise to sunset. During the summer, the park requires proof of residency on the weekends. If you are not from Nassau County, you will have to pay a fee, but there is a way around it. I believe they don't check if you walk in. So I suggest you park nearby, there are plenty of houses to park in front of, and walk.