If you are not in a hurry to get to Watkins Glen, I’d suggest you get to the Mass pike  to NY Thruway and west toward the Finger lakes. At some point west of Schenectady get off the Thruway and take NYS  Rt 20 west. It is mostly 2 lane macadam and goes thru every little village and hamlet – a slow ride, but a nice ride thru central NY. The advantage is that there’s diners and lunchrooms all along the route  the most famous probably is Quacks diner in Madison NY-  everything on the menu is good. 

If you take 17 , the suggestion of the Circle E diner in Hancock is excellent -good hamburger, great pies, great service. 

We’ve never found anything worth writing home about foodwise in Watkins Glen – there must be something, but we’ve never found it. I think I remember that the regular roadfood contributor, Cosmos, who volunteers at the track in the Glen mentioned that he always brings his own food from home- that might say something about the offerings in Watkins Glen. 
  
Hammondsport, Penn Yan, and Geneva all have places with a decent burger and other sandwiches. Several of the wineries along the Lakes have soup and sandwich type service – Wagner Vineyard (Seneca Lake) which also contains a good brewery,  Heron Hill winery (Keuka Lake), and Bully Hill winery (Keuka Lake) come immediately to mind. We’d also recommend Sullivan’s Diner in Horseheads, for the usual diner fare in a historic diner, but also for their Polish specialties served up by a very nice recently emigrated Polish couple.

Cheers, John