There used to be a supermarket called “Whole Foods” in USA that was great for gf foods. I visited it in Washington but it’s a chain. Not sure where or if it is in New York or Florida. You could google it
We were in New York a few years ago and found the restaurant at The Edison Hotel to be fabulous. If memory serves me right, it was called Friedmans. Almost everything on menu was gluten free and we felt comfortable with everything.