While you are staying in Ashland, definately take a short ride over to Center Sandwich (where they filmed On Golden Pond) and go to my favorite in the area - Corner House Inn.
Walters Basin in Holderness is another good spot, I just had this fantastic roasted vegie quesadilla with a key lime aioli. It's on the lake so it's a nice lunch spot too.
There are some nice choices in Meredith too, search the board and you'll find a bunch.
Do you have a favorite cuisine? LemonGrass in Cnter Harbor is great for sushi/asian cuisine.
Great! Here we go:
1. The Common Man right in downtown Ashland is a great place to eat. I love it there. They have this cottage cheese spread / crackers complimentary appetizer bar which is oddly addictive. As far the food is concerned, it's good, unpretentious, American fare, everything that you would expect from the best restaurant in an old fashioned NH mill town. The meatloaf and prime rib are killer. The Common Man has a few other locations in southern NH, but this is the original. The building itself is awesome, I love it. It's tucked right into down town. The floor boards creak incessantly but I love it, especially on the stairs to the 2nd level. This may be the best place to eat in Ashland, it's a classic. The menu is on the website here: http://www.thecman.com/
As you know coming from NH, if you're in Ashland, you're about 5 miles away from Plymouth, NH.
Plymouth has a great Italian restaurant called The Italian Farmhouse. As far as the menu is concerned, this place is essentially an authentic, privately owned Olive Garden done right. They have all the Italian staples, my life loves the alfredo, and I love the classic meatballs. Their marinara is great stuff. I could just spoon it on bread and call it dinner, I swear. They have a wood burning brick oven for pizzas, and they also have a complimentary self-serve bread/oil/freshly grated parmesan cheese bar. It's off the beaten path a bit, which is nice because it's away from the craziness that is known as Plymouth State University downtown.
Hope this helps. I love spreading the news about places hidden away in NH, though.