Hi Marcella! You and I share something in common: a large family with big age spans (my five kids range from 5-18). Disney World is the perfect place for vacation as it truly has so many exciting activites for everyone.
After deciding your travel dates, your next step in planning your Disney vacation is to choose a Resort. If you haven't done so yet, may I suggest you visit this link:
RESORTS?
Take some time to explore the different Resort options, and choose one
that fits your budget and with a theme that appeals to you and your
family. I highly recommend that you stay on property, as you can take
advantage of the complimentary Magical Express from the airport (save
on rental car that way), and enjoy the Extra Magic Hours available only
to onsite guests.
"Must do's" for your older boys will be: Rock 'n Rollercoaster and Tower of Terror at Hollywood Studios, Expedition Everest and Kali River Rapids at Animal Kingdom, Space Mountain, Splash Mountain and Thunder Mountain at Magic Kingdom and Test Track, Mission: Space and Soarin' at Epcot. My 7 year old daughter is a thrill ride seeker and will ride any attraction that she is tall enough for. You may find that yours is the same way and that she won't need to split up.
I would, however, highly recommend Bibbidi Bobbidi Boutique for your little girl. See:
HERE. It is a highlight of our trips for my daughters (5 & 7 years old).
Please take some time to familiarize yourself with the
numerous Resort options, and come back and visit us soon for more planning tips.
Kaylene