I'd plan on 2 days at MK if I were you. I think it's the best park for those ages and the kids will be able to go on many of the rides. Beware of Goofy's Barnstormer - it's fast and doesn't have great restraints (but our kids love it) so hold on to the kids on that one. Many rides at MK (Dumbo, Snow white, Pooh, SW, TTA, Jungle Cruise, Pirates, Train, Carousel, Tom Sawyer, Steamboat, Buzz, etc.) you'll be able to all go on. Our kids love the parades. The show in front of the castle and Belle's Storytime are also big hits. Second choice for young kids would be AK. Again, hold on during the safari! Lion King and Tarzan shows are great and younger ones like the Pocahontas show. Also, the playground in Dinoland is fun. At that age, I think MGM could be a half day since many things they'll be too small or too young for. See Playhouse Disny, Mermaid, maybe Muppets if they're in to that. Fantasmic is great but I might not sit too close to the water as the fire scares some little ones. If you go to Epcot, see the chinese acrobats (kids), the living statues and each country has characters - just ask the CM's where they are - the lines are usually very short. See Food Rocks and the Living Seas (can't think of what else right now). Hope that helps - Have fun!!