Legal Seafood Restaurants, which have many locations on the East Coast, has a nifty gluten-free menu!
First, find a location near year on this page, then click on the menu icon on the right. The one near me has a whole gluten-free menu. They even have GF croutons for the salad, GF Cajun spice, and a junior menu with fish sticks coated in garbanzo bean flour!
Besides several locations in major malls, Legal also has restaurants in Logan (Boston) and Reagan (Washington, DC) airports.