Hi there!
I've been on Weight Watchers since March and have lost 98 pounds so far.
I just got back from Disney World in September and tried my best to stay on program. A few things I found helpful:
1.) NEVER buy soda, not even diet. It's not good for you to begin with, but ESPECIALLY not good when it gets hot out. Drink water, or fruit juice. (Although fruit juice has points, so sticking to water is best)
2.) Look for healthier treats. They are ALL over Walt Disney World. My favorite is the citrus swirl at the Magic Kingdom. The Sunshine Tree Terrace sells them. It's next to the Tiki Room, behind Aladdin (if you're looking at Aladdin from the Jungle Cruise) Non-fat frozen yogurt swirled with frozen OJ. SO refreshing and tasty!
3.) Eat as much sit-down as you can, and discuss the menu with your server. They will accomodate you as much as they can if you just ask. (Sit down is easier to accomodate you....trying to get low-cal, low-fat at counter service is darn near impossible) Although counter service can be pretty good too, you just have to know where to go. The turkey legs are a GREAT snack as long you don't eat the skin. When I went to Epcot, I got a salad with low-fat dressing, and a chicken sandwich with no cheese and mustard instead of mayo. So just search out the menu.
4.) Keep healthy snacks in your hotel room. When and/or if you take a midday break, just have a light snack. Some fruit works, or I like pretzels, or the fat-free or baked chips...things like that.
5.) If you can at all avoid it, don't take the shortest routes. (Basically don't hop from one ride onto the one that's right next to it...) I know with kids this can be tiring, but if you can do maybe a ride or two in Frontierland, cross to Tomorrowland, do a ride or two there, then go to Fantasyland. The more you walk, the better.
6.)DON'T try to count your points. It's futile. Just make the healthiest choices you possibly can. (Allow yourself a treat here and there though...you'll do more than enough walking to make up for it)
When you get back and weigh in, don't be disappointed or discouraged if you gain. It's a vacation!!! Just get back on track the week after you return. I gained 2 pounds after trying my hardest to stay on program, but the following week I lost a sick amount of weight.