We just spent a week wandering through Maine, New Hampshire and Vermont with our 3 sons (8, 14 and 18). Some of the places that stood out in retrospect:
Five Islands Lobster Company, Georgetown Maine: Very nice soft shell lobsters, couldn't be fresher, even better cold the next day. Excellent fried clams (big bellies), good steamers.
Brunswick Diner, Brunswick Maine: Real nice, real diner, real friendly. Excellent cream of broccoli soup, breakfast for dinner suited our boys.
Yesterday's, Jackson New Hampshire: Excellent breakfast - especially good granola, and real maple syrup (of course).
Sly Fox, Jackson New Hampshire: It has the look and crowds of your large generic steakhouse/fern bar, but the marinated sirloin tips were outstanding.
St. Johnsbury, Vermont: If it has good restaurant food, we didn't find it but we had some excellent cheese from the Lazy Lady farm, and some wonderful bread, courtesy of the organic food coop in town.
Lyndonville Vermont: The Miss Lyndonville Diner is locally very popular and was OK (very cheap!), but not as good as the more authentic counterpart in Brunswick.
Rainbow Sweets, Rte. 2 in Marshfield Vermont: Worth a detour, without a doubt. We went twice in 2 days. This bakery/lunch café has excellent Gateau St. Honore, Engadiner nusstorte, chocolate cake, walnut tarts, lots of sweets we didn't try, as well as hot empanadas and bisteeya, which come with a really excellent Greek salad on the side. Plus the proprietor is a hoot as he jokes with every customer, telling everyone to fill up their car with his stuff so they don't starve in the land of rancid mayonnaise sandwiches. Apparently this is a much discovered place, judging from the newspaper and magazine clippings on the walls. Closed Tuesdays.
Parima, Burlington Vermont: OK Thai, but my kids were longing for Dok Bua.
Storm Café, Middlebury Vermont: Excellent splurge to end our road trip. The smoked salmon "lasagna" appetizer was outstanding with lovely salmon, shredded Napa cabbage, crisp crackly tortilla-like layers, and chipotle and wasabi squiggles; the potato garlic soup was devoured; the jerk pork was great, the beef tenderloin with goat cheese and Portobello was good, the risotto needed more flavor but the roasted veggies were great. The white chocolate banana cream pie and fresh berry tart were both good examples of their kind. In true chowhound spirit my 14 year old ordered the crème brulee, even though he was already about to burst, since he tries it everywhere and needed to make a comparison. It was great (and large). It was not as dense as some, but had a lovely vanilla flavor and a silky texture. We fought him for it. Wondering about the 8 year old? They made him very happy with a dish of penne in butter with sautéed chicken breast. It was a very satisfying end to our dining adventures.