Turkey sausage may be available at some places. Last May I had breakfast at Boatwrights and asked what I could substitute for the bacon or sausage and the server said turkey sausage was available (and also mentioned that she went to the Riverside Mill food court to get it). It's not mentioned on any menus, so I don't know if it's available everywhere.
I can also tell you that I've gotten many different answers at various times to that question so even if they don't have turkey sausage, there are other options like fruit or an egg. At one of the resort food courts, I remember being able to get a container of the applesauce instead of the meat. I haven't, however, tried asking specifically for veggie sausage, so that may be another option.