Hi Kimberley! Your children are at wonderful ages for a visit to Walt Disney World! What fun you're going to have!
Since you're planning to visit for four days, you can devote one day to each park. Because you're not staying at a Disney resort, I recommend that you avoid visiting the park hosting Extra Magic Hours for Disney resort guests each day, since you won't be able to take advantage of that extra park time and those parks can become more crowded on those days. Your little ones will likely love the fun attractions at the Magic Kingdom most of all, so you might want to save that park for last.
Plan to arrive at the parks each day before they open. When you get to the parks early, you can usually experience a lot of attractions with minimal waiting. Arriving early is especially important when you're visiting at busier times of year, such as Spring Break. (You can find the daily park operating hours on the
park calendars.)
For your late March vacation, I'd recommend you visit the following Disney World parks each day:
March 24 Epcot or Hollywood Studios
March 25 Animal Kingdom or Hollywood Studios
March 26 Magic Kingdom or Epcot
March 27 Animal Kingdom
March 28 Magic Kingdom
Try to book your character breakfast in or near the park you're planning to visit that day, and if possible, reserve your breakfast before the park opens. For instance, if the park opens at 9 a.m., try to book an 8 a.m. character breakfast. Chef Mickey's, Tusker House, and Crystal Palace offer great character breakfasts for young children. An added bonus is that kids under 3 dine free at those character buffets!
Come visit us again here at the Moms Panel if you have more questions! We'd love to help!