Where to eat near Bethpage State Park?
For breakfast I'd head down to Amityville for Cornucopia's Noshery (my fav in the area) or Park Avenue Grill (just down the block). About a 15 minute drive. Nothing I'd really recommend that's closer.
For lunch that's pretty darned close to BSP, go to Farmingdale--literally about 5 minutes away. There's a bunch of places to eat there: Tiny Thai, Dominican 4, Caracara Mexican, Croxley Ales (if you want a beer from a vast list of on tap), The Republic (lesser beer selection, better food), Library Cafe