Their menu is very limited when you are going for gluten free. You can either have a salad, one or 2 soups, and oh, another salad. Basically you must like you're veggies order to eat here.
My favorite is the Fuji Apple salad, every thing is gf on that, so no subs are needed. Their creamy tomato soup with out croutons is very good, I can eat that all day (and gain ten pounds while doing it for it is very high in calories). Also if you are there on a day they have black bean that is also a gluten free soup.
If you are looking for sandwiches, Jason's deli is the place to go even though they just use udi's bread, but still it's a start. One day I would like to see Panera to offer gf bread even if it is store bought.