Hello Antonella!
This is a great question! As a mom of a 4 year old myself, I can totally appreciate your question. If I had to choose my daughter's 2nd favorite park (after Magic Kingdom), I would say Disney's Hollywood Studios. Mainly because they have an area called Animation Courtyard which features attractions such as Voyage of the Little Mermaid, which is a live action show featuring Ariel. There is also another show called Disney Junior - Live on Stage! This show features Jake and the Neverland Pirates, Doc McStuffins, Sofia the First and Mickey Mouse Clubhouse characters. It is one of the best shows in Walt Disney World for preschoolers! There is also Toy Story Mania which features the characters from Toy Story! Epcot does not have too many attractions for the little ones but is great for adults! Particularly if you enjoy sampling foods from different countries!
Here are a couple of "must see attractions" my little ones can't live without: "Toy Story Midway Mania" and “Disney Junior – Live on Stage!” at Disney's Hollywood Studios; "Peter Pan's Flight", "Buzz Lightyear's Space Ranger Spin", "It’s a Small World” and the "Magic Carpets of Aladdin" at the Magic Kingdom, "The Seas with Nemo and Friends" at Epcot and "The Boneyard" play area at Disney's Animal Kingdom! Also, you don't want to miss meeting your favorite characters, please visit:
Character Experiences. If I can offer any more "Visiting Disney with Preschoolers" tips, please feel free to send them my way!
Happy Planning!
Yael