Where is the best gluten in DC?

A dear friend of mine has been gluten-free for more than a decade after a celiac diagnosis. Now his doctor wants to re-test him, which apparently means that for a week he should start eating all of the gluten to see how his body will react. When it comes time for him to dive in, I want to be prepared. He's been deprived for more than a decade, and he deserves only the best things. He is a very excellent human. So here is the question:

If you had only a week to consume all the best glutenous foods in DC, where would you go and what would you eat?

While "hop a train/flight to NYC/Paris/Italy" are totally valid answers to this question (and under consideration), I'm specifically looking for gluten in DC as a response to this post.