There are plenty of fruit items you can have as a snack option, most CS places have something gluten free but you may have to ask for it if you can't see an option on the boards above the registers. TS places you should have a note made on your account that you need gluten free foods, that way you can discuss with the chef and their team what options they can arrange for you they are very good at this so don't worry about asking to speak to them.