Hi there, Kristin!
With a three-year-old, I'd unreservedly recommend
Port Orleans: French Quarter. This smaller, quiet Resort offers all of the theming and amenities of its "beachy brothers," but without the overwhelming crowds you will sometimes encounter at the others, both of which are convention facilities.
The Resort offers both a playground (built on rubber flooring overlaid with soft artificial turf) and a pool with a slide. The pool area, adjacent to the playground, boasts a small kiddie pool in addition. And every day, Cast Members come out to lead all of the children in poolside games and contests.
Again, the French Quarter might not have the excitement of the Dig Site (
Coronado Springs Resort) or the water play area (
Caribbean Beach Resort), but the smaller size might be beneficial to you, both for ease in watching your little one and for not subjecting your little one to
so much at once.
Finally, the size of the French Quarter means that nothing is far from anything else. This means that a sleepy little one can be carried over a relatively short distance if need be, and there are no long bus rides around the Resort to try a tired Mouseketeer's patience.
I hope these suggestions help you; please drop me a line and let me know where you decide to stay.
See you later, celebrator,
-Deborah B.