Being on the insulin pump is wonderful! I cannot even compare my pre-pump Disney trips with my post-pump Disney trips. It is heaven. I have been on the pump for 10 years. If this girl is 18, she should have a thorough understanding of her diabetes and her pump and what to do.
Does she count carbohydrates? If so, then meals and snacks should be easy. She shouldn't have to order anything special or leave anything off.
BUT SHE MUST KEEP GLUCOSE TABLETS ON HER AT ALL TIMES. I cannot stress that enough! I have gone to Disney before with the cocky attitude that "if my blood sugars drops, there are snacks and cokes everywhere, I'll just grab something." Well, I learned the hard way. All the walking makes it hard to keep your blood sugar up. Insulin reactions can hit quickly and if you're stuck on a ride, in a line or in a show, you can't go grab a snack. If she has glucose tablets in her fanny pack or backpack, she should be fine.
She should check with her doctor about her basal and bolus rates before she goes. (If she's not comfortable figuring them herself - my doctor encourages his patients to micromanage their own care). I find when at Disney and doing all that walking I don't need to take the same number of units of insulin per grams of carbs as I do at home. Adjusting that accordingly will help to avoid the low blood sugars.
I do not know how long she has been diabetic. I have been diabetic 26 years. As far as the other students not wanting to stop when she does - how has she been around these kids in the past? All my friends, family, and my godchildren (ages 9 & 5) KNOW that if I say I need to stop, I'm not kidding. It is not negotiable. You just stop and they will have to stop, too. Now, I don't actually stop that much. EVERY time we take a bathroom break at Disney, I check my sugar. If I "feel" low, I eat a snack (from my backpack) as we're walking. Often when I really need to rest, we ride something slow, like Small World, the train, Tomorrowland Transit Authority, etc. Something you can get on pretty quick, but the kids still feel like they're doing something besides sitting on a park bench. I can check my sugar and eat right on the rides. I also keep a tiny flashlight in my backpack for checking my sugar inside dark rides.
The main things I would tell her are: Don't ignore how you feel, always have snacks, water and glucose tablets in your back pack, check your sugar at least once an hour, and wear comfortable shoes and pace yourself.
I am wondering why this girl's parents are aren't sure if they are going to let her go. Is she not under very good diabetic control? I have a 7 year old diabetic on a pump in my sunday school class and she knows the ins and outs of diabetes as well as I do. Her mother lets her go on trips with us all the time.
Let me know if I can answer any questions!