Grant Park has become an athletic center with a hockey rink, baseball fields, workout areas, and a playground. What happened to nature? Well, there is a pond and half of it is fenced off (to prevent fishing from that side) where trees grow relatively undesturbed. There is also a small area that trees grow with ivy all over, and not the poison kind, so don't worry. There used to be a cache near where I placed this one (GC3WY2Y). It was my third find and I could not let this spot go, so I placed this cache.
Open during daylight hours. 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 $10 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.