Hi Kelly, Thanks for visiting the Moms Panel!
Due to the popularity of Disney's great restaurants, reservations are strongly recommended. At the Grand Floridian, for example, the 1900 Park Fare has the Supercalifragilistic character Breakfast. See:
HERE. This popular breakfast fills up quickly, so without reservations, you could have trouble getting a table. You
may be able to eat at the Grand Floridian Cafe without reservations but it's better to be safe than sorry. I'd go ahead and book ahead of time.
You can browse the various restaurants on this link:
HERE. Dining reservations can be made as much as 180 days in advance by calling: 407-WDW-DINE or you can book online at the link provided above.
Hope this helps and that you have a Magical vacation!
Kaylene