You'll have time to do everything. Plan to go in Winter/early spring if you can. Summer in Florida can legitimately ruin your trip.
If you really stretch it out you'll get:
Animal Kingdom - 1 day
EPCOT - 1 day
Hollywood Studios - 1 day
Magic Kingdom - 1 or 2 days
Universal - 1 day
Islands of Adventure - 1 day
Legoland - 1 day
You're going to be so burnt out by day 4 though. I did 4 parks in 4 days before and by the end I was skipping rides etc just because I didn't want to walk back across the park.
If you really are committed to that many days I'd include some days just to explore the city/state or chill at the hotel.
Edit - woops this has been covered. On your off days you could go to the beach for a day or two if you don't mind driving.
If you really stretch it out you'll get:
Animal Kingdom - 1 day
EPCOT - 1 day
Hollywood Studios - 1 day
Magic Kingdom - 1 or 2 days
Universal - 1 day
Islands of Adventure - 1 day
Legoland - 1 day
You're going to be so burnt out by day 4 though. I did 4 parks in 4 days before and by the end I was skipping rides etc just because I didn't want to walk back across the park.
If you really are committed to that many days I'd include some days just to explore the city/state or chill at the hotel.
Edit - woops this has been covered. On your off days you could go to the beach for a day or two if you don't mind driving.