Hi, Shannon!
Your niece isn't going to believe her eyes when you all walk into Disney's Art of Animation Resort! The Finding Nemo Family Suites are so cool! She'll feel as if she's walked right into the movie around
The Big Blue Pool! In fact, I recommend taking some time to tour all of the different sections of the Resort because it's really awesome!
The Disney buses do not travel between Resorts, so the best thing for you to do is to hop on a bus to Magic Kingdom Park where you'll be able to then take the monorail over to Disney's Grand Floridian Resort & Spa. I encourage you to allow 90-minutes for travel time between Resorts in case you have to wait for transportation. If you're driving, it should only take you about 20-minutes, but I would allow 45 just in case. I'd much rather be early than late. Plus, that will give you some time to relax in the gorgeous lobby!
You will just love breakfast at 1900 Park Fare! I had breakfast there with my daughter a couple of weeks ago and we really had a great time! Be sure to try the Strawberry Soup! It's amazing!
Wishing you and your family a Pixie Dusted vacation!
~Jackie