I agree with pp's that 2 at MK and EP is a good idea. 1 day a tthe other 2 is fine.
And I've been wit a 4 and 5 year old and I would recommend skipping the water parks unless there is a huge interest there. At that age many kids are enthralled by the resort pools - and swimming for an afternoon and a couple of evenings is enough with the 'wet' stuff to keep them satisfied. Besides - the littler kid stuff at the water parks isn't too much different than you can get locally - with wave pools and sprinklers.
So I would skip the water parks and go to the main parks more.
And I've been wit a 4 and 5 year old and I would recommend skipping the water parks unless there is a huge interest there. At that age many kids are enthralled by the resort pools - and swimming for an afternoon and a couple of evenings is enough with the 'wet' stuff to keep them satisfied. Besides - the littler kid stuff at the water parks isn't too much different than you can get locally - with wave pools and sprinklers.
So I would skip the water parks and go to the main parks more.