We will be there in 5 weeks (actually, 5 weeks today we will be at Disovery Cove).
Fly Virgin - book flights separate - collect airmiles and use off next years flight back to Florida!
Book accommodation separate - think I read that Mamablue has stopped at the Sheraton in Lake Buenavista. We stop at the Sheraton Vistana Villages on the really quiet end of International Drive. 2 bed apartment, 2 bathrooms, kitchen, washer, drier etc.
Personally, I would do one day park, next day pool.
My boys were not that bothered about Disney (possibly a boy thing?) although we did do all Disney parks the first year we were there. We also did all the water parks, Universal and Seaworld.
Last year we only did a water park, Islands of Adventure, Seaworld, Universal and we went to Clearwater for our middle weekend.
This is year we are doing, Discovery Cove, Busch Gardens, Aquatica, Islands of Adventure and possible Cape Canavaril.