Hi Christy,
This is a great time to go to the Walt Disney World Resort. The parks are filled with magic!
Magic Kingdom is a great place to visit. There are many fun attractions such as Buzz Lightyear, Space Mountain, Big Thunder Mountain Railroad, Jungle Cruise and Dumbo. This park does not have many full service restaurants. Crystal Palace and Liberty Tree Tavern will be easier to make an Advance Dining Reservation than Tony's or Cinderella's Royal Table. You may want to hop on the monorail and eat one of the restaurants located at any of the monorail resorts. Try the Wave, California Grill, Ohana or 1900 Park Fare.
This park will take you two days at most to cover this park. Your 16 year old may find it does not have enough thrills. For bigger thrills, Disney's Hollywood Studios has Twilight Tower of Terror and Rockin' Rollercoaster with Aerosmith as well as great shows. Your six year old would like this park as well.
Epcot is really two parks in one so it is a great way to spend your time. And if you have an animal lover, than Animal Kingdom might be on your list as well.
Wishing you a magical vacation!
Beth