I wish I could help more, my gluten issue is pretty mild and resolves with a Benadryl so contamination isn’t going to ruin my day as much as make me a little drowsy. (And I can counter that with some caffeine!)
I try to stick to places I can order just a steak or something easy. Mythos I believe ive heard is pretty good. Hard Rock has a gluten free menu with gluten free bun burgers—I’m excited about that. Also you can bring in food since it’s related to a food “allergy”. Security will allow it through.
I’ve done some googling and have my stuff fairly planned out. I wish I could help you more!