How Could A Six Flags Trip Be Managed With Type 1 Diabetes And Celiac Disease?

My friend invited me to Six Flags last year. I had diabetes but not celiac, so I am more concerned about that. Usually, they have dinner inside the park, but you bring your own lunch to eat outside the park. So I'm fine for lunch, but not dinner. I don't want to be too much of a hassle during this. They do not allow food inside the park. So what should I do?
By the way, I cannot eat things on the inside in case they contain gluten. Just to be on the safe side.