Hi Kathryn! Planning a Disney itinerary is not always easy so don't think everything has to be set in stone. Once you arrive you will find different things that might interest you and often you will cancel one dining to grab something else.
My family does set aside specific days for each park. We also buy park hopper tickets in case we want to go back in the evening to enjoy fireworks in another park then the one we were in during the day. I have always felt the
Park Hopper add on option was worth the money as it gives you so much more freedom to come and go and do all the fun activities offered in the parks.
Right now I would plan for at least one full day in Epcot and probably two full days in the Magic Kingdom park. Hollywood Studios has closed quite a bit of the attractions there to make room for the construction of Star Wars and more Toy Story so this is more of a 1/2 day park. Animal Kingdom is also what I consider a 1/2 day park. That does not mean you can't extend your time by doing some of the attractions several times and doing EVERY attraction possible. You can even plan resort pool time on the days you hit these two parks.
You also should definitely save some time for
Disney Springs. This is perfect for a 1/2 day visit and make sure you plan some meals there. They have opened up some amazing table service restaurants as well as some awesome quick service spots.
If your family enjoys the water rides consider a day at one of the Water Parks. I don't recommend this if you are coming in the winter months as the air does get cool here even in Florida.
So, recapping my suggestions: 2 days at Magic Kingdom, 1 day at Epcot, 1/2-1 day at Animal Kingdom, 1/2-1 day at Hollywood Studios, 1/2 day at Disney Springs, and if right time of year a day at a water park.