Two years ago I went on program and actually lost two pounds to put me over the 30 pound hump. I didn't count points. I did, though have my usual home breakfast of raisin bran everyday except when we went out, which was only once, I think.
When we ate buffets: Crystal Palace and Chef Mickey's, I always had a big plate of salad and/or fruit first. I tried to take just really little porttions of high point fare like lasagne.
For desserts, I only ordered one at Restaurant Marakesh, ate the whole thing and savored every bite! Otherwise, I tried to stick to just one bite of sweets when the menu was prix fixed.
With all the walking you'll do, the water you'll need, and ahem the sweating, you'll probably be fine with some common sense.
(It probably didn't hurt to be pushing a double stroller full of fifty or so pounds of preschoolers, either.)
Have a wonderful trip!