I was worying about this exact thing, because I have been very concerned with what I eat lately.
However, I realized how excited I was about the food and pretty much all the food I'll be eating, as this is my first memorable trip to WDW and I start college soon. I'm going to *try* to watch what I eat, but in addition, I'm going to be usuing the elyptical for minutes every morning in the AKL gym and doing calisthenics before bed, which is what I usually do anyways.
Of course, this is avacation, and who REALLY want to work out?
You're a vegeterian, so you're eating options are limited anyways. I would just play it safe. Hungry at the parks? Grab an apple instead of an ice cream.
Little things that will really help in the long run so you don't have to stress over counting the million of calories you will most likely consume in a few days.