The drive from NY to AC isn't really that long, and I would not bother to stop for lunch along the way--just get yourself down there and eat in AC. If you really have a mind to stop, you could do it in Red Bank, which is just a bit short of halfway, or Asbury Park, a few minutes further south. Red Bank's good restaurants are a little closer to the Parkway (about 10 minutes) while Asbury's are about 20 minutes away from the road. Asbury is arguably the more interesting place to visit, being mildly renowned for its musical history, but its dilapidated charms might not be for everyone. Red Bank is much more prosperous and thriving, but it isn't on the ocean, so no view or boardwalk.
If you want to drive further south, there are more beach towns with boardwalks, all about 15-20 minutes from the Parkway.
Your roll of quarters would be fine but I would strongly suggest renting a car with an EZ-Pass transponder, if that's at all possible. There are a ridiculous number of toll collection points along the Parkway and your trip will be much faster if you have EZ-Pass (with it, you don't have to stop, whereas the cash lanes always have a backup).