MK is a best bet.. Dumbo, Aladdin's Carpet Ride, The Carousel, Winnie the Pooh, It's a Small World, the Tea Cups (you don't have to spin), Mickey's Fair (Meet 'n Greet with the Mouse himself), the toddler Playground and the Boat play area (bring extra clothes if the water is turned on), and maybe The Country Bear Jamboree. MGM ... Playhouse Disney. AK... Safari (do NOT do the Tree of Life/ A Bug's Life, it is dark and there are noises which scare little ones.. DS5 freaked out for three years in a row in it and would not go back until this past fall), the train to & Conservation Station (petting Zoo), AK also has an awesome Child Rest Center.
Definitely get your naps in, have them drink lots of water and put on sunscreen. The weather has been nice recently, but we're getting close to the rainy season so it may be humid.