Lana,
If it's in your budget, I highly recommend buying a book or two to aid in the process. I am particularly fond of Passporter (
www.passporter.com) but there are many great ones out there. Three of your kids are old enough to take an active role in the planning, so put them to work! Highlighters or post-it notes will be great for them to mark their must-do rides, interesting attractions, or restaurants they'd like to try, You can compile everyone's list later and get a good plan for each park day. To decide on those park days...
I suggest looking
here at the Calendar pages. You can select the month and park you want and look at each daily schedule. Click on dates to see parade and show times and extra magic hours (EMH). Decide if you are morning or evening people, so you know which extra hours to utilize. We're night people in my house, so we love the extra 3 hours of park time and we try to take advantage of that whenever possible. After you know where you're going each day, you'll be ready to make meal reservations.
For dining I suggest visiting
www.allearsnet.com - click on dining, then on 'The Menus!' and you can see very current menus and pricing for every eatery on Disney property. In fact, this website is an excellent resource for all aspects of your planning. It's not an official Disney site, but it is incredibly detailed and the information is pretty current. If you want to eat at any table service or character meals you
must make those reservations in advance. They are accepted 180 days in advance and I recommend making them ASAP by calling (407) WDW-DINE.
I hope this helps you dive into your planning, and feel free to ask us if you have any more questions!