Vacation advice

[midtown]

I was just in Florida for about 18 hours which included Key West for about 6 hours. THE weather was perfect and it made me want to sit on the beach with my wife and son for a few days. I tried to stay over and book them a flight out today but nothing available so now I'm back here freezing. Any ideas on kid friendly place within a 4-6 hour flight? KW doesn't really have great beaches and is more of a party, sailing, fishing place IMO.