In Portsmouth I suggest you check out:
Jumpin' Jays Fish Cafe (great fresh fish, raw bar, cocktails)
Black Trumpet Bistro - chef from famed Lindbergh's Crossing. Shoot for a seat in the wine bar upstairs.
Friendly Toast - great big yummy brunch
Brown's Lobster Pound (good steamers, fried lobster tails, etc.)
On the same road as the Wentworth, the Ice House. We usually get a lobster roll and onion rings and sit at a picnic table under the trees although there is inside dining (order at the table if eating inside). My friend who lives in Hampton Falls recommends Browns and Markeys (across from each other) in Seabrook for casual fried seafood and steamed lobsters.