I've lost 91 lbs in 8 months doing WW, and I've been to WDW twice during that time. The trick for me was sticking to a light breakfast and lunch, then letting myself really enjoy dinner (ordered what I wanted, tried to stick to eating only half, But had dessert every night even though I couldn't always finish it!). I didn't try to count points, as it was just too hard not knowing how things were really cooked. But I lost a pound while we were there for 4 days in March and a half pound during the last week long trip in June. I did exercise most mornings at the gym or laps in the pool. And we did so much walking that I got in tons of extra exercise.
First, try to follow all your usual practices -- order salad dressing on the side, lots of water. Any place you go will happily make you an egg beater or egg white omelet -- just ask! With just veggies this is a delicious low-point breakfast. If you like it, aim for fish and seafood as it's much lower in points. At the fast food places, even if you want a cheeseburger or hot dog, you can usually replace the fries that come with it with fresh fruit or carrot sticks.
Great places to eat on WW:
Olivia's at OKW for breakfast -- they have an eggwhite omelet that comes with wheat toast and fresh fruit. YUMMY!
The Harambe fresh fruit cart in AK has an amazing selection of cut up fruits. In June they even had fresh tomatos with a vinaigrette for dipping -- it was FANTASTIC!
Tusker House at AK also has a great salad with the same vinaigrette dressing.
Cosmic Ray's has a great chicken caesar salad and they'll be happy to put the dressing on the side. They also have vegetable soup that I assumed was low in points (but high in sodium) and was very good.
Nine Dragons at Epcot has a Drunken Chicken Salad that is just lettuce and veggies with shredded chicken that was marinated in a sake marinade. Comes with a ginger dressing on the side that is excellent. Also love their wonton soup and it too is probably very low in points.
I love O'Hana's. I fill up on the stir-fry veggies and a little lo mein, then pig out on the huge shrimp! I usually allow myself a wing or two, but I pull of the skin, and a few bites of steak as well. I'm always satisfied there.
Mitsukoshi Teppanyaki at Epcot is also great. They'll happily cook your hibachi with no oil or butter if you ask and they have a variety of low point seafoods to choose from.
Most importantly though let your inself indulge some! This is vacation and if we're too hard on ourselves, the plan won't work for life. Like I said, I had dessert every night in June and still LOST weight! And now if I'm out at dinner I find it easier to say no to dessert because I know the next time I'm at WDW, I can really enjoy the desserts then!