How lovely! We went at Easter a few years ago and had a brilliant time. But Easter might not be great if your boys have important exams in the summer. If you get to the parks very early you can avoid the worst queues. We have 2 teenage boys. We stayed in a villa just off HWY 27 (estate called Highland Reserve) and hired a car. A villa is great for teenagers if it comes with pool, snooker table and darts, my boys loved it. And they are so huge, these villas. With huge TVs everywhere. I loved the washing machine and tumble drier even more, sad eh.
Foodwise there are loads of good value restaurants around there - hardly gourmet dining but all you can eat buffets which suit teenage appetites very well. E.g. Sizzler
We also did an indirect flight via Newark and this was loads cheaper.
We booked with this travel agent which was only very slightly more expensive than DIY (£120 more IIRC) and they are so knowledgeable and helpful and make it all very easy for you. Also you get all the financial protection.
We agonised for a long time over the 'which parks' question. We were advised that doing them all in 2 weeks is too much, so we settled on unlimited Disney and a day each at Seaworld and the Kennedy Space Centre. This worked very well. I would have to disagree about Magic kingdowm being too young and girly - there are still some amazing rides and the processions, fireworks and general clever theming are all fantastic for all ages. It was actually vey funny watching two strapping lads get all misty eyed when meeting Minnie Mouse and Sleeping Beauty! Also with unlimited Disney you get the 2 water parks, Blizzard Beach and Typhoon Lagoon, both fabulous. We also felt that Disney parks were more iconic somehow.
Admittedly we haven't been to Universal Florida but we have since been to Universal Hollywood and still feel we made the right decision (but no Harry Potter at Hollywood).
I guess the answer is to go for 3 weeks and do them all!
at Epcot being dull! Test track is awesome! And all the fantastic restaurants.
I'm sure you will have an amazing time whatever you decide
I agree with the various recommendations for books to read.