Kandice,
There are a lot of pointers that can help out, so keep asking questions, and you can get more as we go along!
If you have a double stroller, bring it. Kids are not accustomed to so much walking, and the stroller helps keep them from getting tired too early, and it also helps you keep an eye on them. If they are in the stroller, there is less chance of them wandering off. Don't worry that your son may be past a stroller age. My 6 year old still rides.
Use counter service to keep your food budget in line. Too many parents of preschoolers schedule table service meals for every meal. That is just too much food for them, and you find yourself wasting a lot of money.
Last tip is to do something for
you. You have to have fun too. If it is in your budget, book them into the
Child Activity Center at one of the Deluxe resorts and have a night out to yourself! They are very well run, basically like a day care, and they even get dinner there. And you can hit some of those roller coasters!
Have a magical vacation!