Summit Point: lunch at Chez Summit, dinner at Avanti in Charlestown. I've heard the buffet at the horse track is very good, will have to try it some day. Lots of places in Winchester, from steak to seafood to Italian to Mexican, to pub food.
Beaver Run: bring your own lunch. For dinner, try the Quaker Stake and Lube at exit 3 - lots of fun and where else can you eat UNDER a Corvette or Healey 3000?
There is also a very good Italian restaurant just past the turnpike entrance, can't think of the name right now.
Pocono: bring your own lunch or a ton of money. The food won't kill you, but you sure won't brag about it either. If in the mood for an expensive dinner, I'd highly recommend the restaurant at the Blakeslee Inn. You don't have to dress up for it on a race weekend. Even if wearing jeans and a clean tee-shirt, they still provide excellent service, and the food is outstanding. Entrees are around $25. There are quite a number of decent restaurants around the track, I've tried many and rarely had a bad dinner. There are also pizza and sub places, including a decent one in Blakeslee.
Nelson Ledges: as another poster said, I really like the track.
Lime Rock: about like Pocono for lunch. For a filling, inexpensive dinner, I often stop at the Sharon Diner (not sure that's the correct name, but it's in the little shopping area across from the gas station and Sharon Motor Lodge). The food is decent diner style. Warning, it closes early. I haven't found many inexpensive close places, usually have to do some travelling or pay a high price and dress decently (not jeans).