The options out in Harvard are limited. The city basically relied upon having the large Motorola plant within its borders and that plant closed five years ago.
The Swiss Maid Bakery is off the square and does a pretty decent job with pastries and the price is about half of what you would pay in Chicago.
We tried a pizza/Italian place on US 14 but that was pretty awful. The spaghetti was beyond overcooked.
There is a German place called the Heritage that is near the hotel on US14 that has a pretty decent menu but I have never had teh opportunity to try it. I am not sure it is open for lunch.
I would recommend the Royal Oaks Orchards for lunch, in season, but we are avoiding the place as they charge a $3 "parking fee" on weekends EVEN IF you make a purchase.
There are a few places in Hebron that are pretty good - the Bake House, the diner (name escapes me), and Crandall's - but you are talking a 10 miles drive.