Hi Lynn,
I think your children will love the magic at the Walt Disney World Resorts!
Currently, you can book a room only 499 days out. This gets you to the summer of next year. As for dates for events, they usually come about six months prior.
Disney is most crowded during the week between Christmas and New Years, President's Day week, Easter Week, Thanksgiving week and summer from Memorial Day through the second week of August. This is when the kids are out of school.
If you are willing to take your children out of school, October is my favorite month to go. The weather is perfect and there are great bonuses such as
Mickey's Not-So-Scary Halloween and
Epcot's International Food and Wine Festival. The week after Thanksgiving is great if you want to experience the holidays.
If you need to go while school is out, Easter week is the least crowded of the options without the hot weather.
Wishing you a magical vacation!
Beth