I have a gluten allergy as well and live in NYC. Feel free to contact me if you have any questions.
Sambuca is absolutely amazing and my favorite restaurant in NYC. There is a deli in Chelsea Market that I haven't tried yet but they sell gluten free sandwiches. It's called Friedman's deli.
One place you MUST try is S'Mac. It's difficult to get to - in the East Village - but it is amazing gluten free macaroni and cheese. About a million different kinds. Delicious.
Risoterria is the best place I have found for pizza. They also sell delicious risotto. And their desserts are to die for. Tiramasu, cupcakes, oreo cakesters, twinkies, black and white cookies, apple pie, etc, all gluten free.
Any other questions feel free to ask!
"This table, he is over one hundred years old. If I could, I would take an old gramophone needle and run it along the surface of the wood. To hear the music of the voices. All that was said." - Doug Wright, I Am My Own Wife