Hi Jkms.
Thanks for visiting the Moms Panel with your great question!
You're going to LOVE the Deluxe Disney Dining Plan. It allows you so many opportunities to experience the magic of dining with the Characters!
There are some great Character Dining opportunities at which you can experience some of your granddaughter's favourite characters! My favourites include
'Ohana's Best Friends Breakfast featuring Lilo, Stitch, Mickey and Pluto,
Cape May Cafe which features Minnie, Goofy and Donald, and
Chef Mickey's which features Mickey and many of his friends!
A few others to consider that are ideal for her age would be Hollywood & Vine for
Disney Junior Play 'n' Dine and
Akershus Royal Banquet Hall for Princess Storybook Dining. Akershus is my personal favourite of all and I recommend it most highly for breakfast time.
The least crowded reservation times are generally the earliest morning reservations and the 'off' times for lunch or dinner such as mid-afternoon for lunch or 4pm for dinner. Eventually, all times will fill up and you'll find that the volume of Guests at each location remains fairly constant. You will however receive personal attention at your table with each character while you dine at any of these locations!
If you'd like further recommendations or assistance with your plans, please write me back and I'll be thrilled to help you out!
Wishing you a simply Magical time at Walt Disney World with your granddaughter!
Kirsten