There's a Checkers on Hillside Ave a couple of blocks east from the 179th St F station.
There should still be one on Parsons Blvd, a couple of blocks south of the Grand Central too. I haven't been over there in a year or so though. I've seen them in Nassau also.
Their fries and even their burgers are surprisingly good. They look on the signs like they should taste like derriere, but they're pretty standard fast food fare. Their signs are more honest than the big chains.
Checkers also sells their fries frozen. I think I've bought them in Target.