Hi Andrea:
I'm a parent of two boys, ages 5 and 4, who have been traveling to Walt Disney World since they were infants, and I would love to share some of my family's must-dos for our Disney World vacations. Your family may have different tastes, but hopefully these recommendations will be a good start to planning your trip.
Among many other things: at the Magic Kingdom, we always ride the Jungle Cruise, Peter Pan's Flight, Mickey's PhilharMagic, and it's a small world. At Epcot, we take in Spaceship Earth, Living with the Land, and tour the countries of World Showcase. Highlights of World Showcase are the Kidcot Fun Stops, which are craft stations where children can draw and color while learning about different cultures as they interact with Cast Members from around the world. Our must-dos at Hollywood Studios include Toy Story Mania, Star Tours, and Muppet Vision 3-D. At Animal Kingdom, our family always rides the Kilimanjaro Safari and visits Conservation Station. Of course, every family is different, and to have a successful trip, you will have to take your childrens' likes, dislikes, and comfort-level into account.
You'll likely find that Deluxe Resorts have more activities planned during the day for families (my family loves Animal Kingdom Lodge), but all Resorts, from Value to Deluxe are great Resorts for families. For my family, we never rent a car. We use Disney's Magical Express to and from the airport and complimentary Resort bus, monorail, and boat transportation to get around Disney World property.
As you enter the parks, pick up a Times Guide for parades and show schedules throughout the day. Also have a look at
Disney's in-depth planning page for traveling to Walt Disney World with younger children.
My best advice is to relax, follow your childrens' pace, and enjoy.