I know that when I meet up with moms from different areas we are always looking for places in the middle, new places, etc. I thought if we all list a few places we know of and the town and cost for residents vs. non-residents we could all save ourselves some time.

I'll start...

Mount Sinai-
Heritage Park, corner of North Ocean Ave (83) and Route 25A. Free. Winding trail, 2 playgrounds, soccor fields.

Stony Brook Area-
Avalon Park- Trails through woods for hiking, duck/geese pond. Near Stony Brook Harbor/Three Village Inn. Free.

West Meadow Beach- Free for Brookhaven residents. I think it's upwards of $20 for non-residents. On the sound, playground, bathrooms, sprinkler sand area, ice cream truck, no concession stand.