Hi Tricia,
I like your plan to spend two days in Magic Kingdom. You mention that your daughter loves Mickey Mouse and friends as well as princesses, and you can see those characters at Magic Kingdom! I suggest that you watch the
Walt Disney World planning video, as well as visit the
Walt Disney World planning for little ones page. Both of these resources will give you lots of information on what is at each of the theme parks.
Since you mention that your daughter loves Dory and Nemo, you might want to head to Disney's Animal Kingdom to see
Finding Nemo - The Musical. While you are at Disney's Animal Kingdom, a ride on the Wildlife Express Train out to Rafiki's Planet Watch can be fun. At Rafiki's Planet Watch, she might enjoy Affection Section, where she can pet animals. My daughter loved brushing the animals there when she was a toddler! Also for Dory and Nemo, you might want to head to Epcot to ride
The Seas with Nemo & Friends, which takes you underwater with characters from this story. At Epcot, my daughter always enjoyed a ride on Journey into Imagination with Figment, and loved heading to World Showcase to color at the Kidcot Fun Stops. Given your daughter's interests, if you were going to skip a theme park, I would skip Disney's Hollywood Studios. However, if you do want to head there to see some Disney Junior characters, it could be a half-day afternoon park that you visited after a morning at either Disney's Animal Kingdom or Epcot.
I would love to help you plan more Tricia; however, I am limited in the space that I have to answer. Please write back if you have any further questions!