Ann:
We have a family of 6, with four children who span 9 years, so I feel your pain of not necessarily fitting into the family-of-four, one-size-fits-all vacation plan!
I would definitely recommend the Magic Kingdom. Not only because it is iconic, but it also offers something for every age with just a few attractions requiring height restrictions. If you think the older ones may roll their eyes at heading to Fantasyland, encourage them to look for hidden Mickeys on the attractions.
I would scratch Epcot, as all of its headliner attractions, Soarin', Test Track and Mission Space have height requirements, leaving your youngest ones possibly out of a good part of the day. Now we're down to Animal Kingdom and Disney's Hollywood Studios.The second park depends on your family. If your family enjoys animals or loves music, consider Animal Kingdom. Our family never misses Flights of Wonder, and Nemo the Musical and Lion King provide spectacular entertainment in air conditioning during probably the hotest month of the year when you'll be visiting.
However, with that said, I would strongly recommend Disney Hollywood's Studios as your second park. Again, the park offers just as much for the younger set as for the older ones and my teenagers still love Muppets in 3D. But what makes it my pick is that the park is featuring its
Frozen Summer Celebration, complete with a parade, sing-a-long, ice-skating rink and special fireworks. Layered on top of all DHS has to offer like Star Tours, the Great Movie Ride and Toy Story Mania, it would be my pick. Make sure and consult the
park calendar for your dates to make sure Fantasmic is showing to cap off the day.
Wishing y'all a magical vacation!
Whitney