Your Disney trip is so long, I think you could shave a few days and do both if you want. That being said, I love Key West. It would be my choice now but I voted for St. Augustine because you have kids.
my favorite things in Key West aren’t really kid friendly. We enjoyed Truman’s Little White House and Hemingway’s House but doubt that kids/teens would. Our fave part though was lounging all morning around our rental’s pool, heading to brunch, and then using our bar cards to spend the bulk of the day bar hopping, day drinking, and listening to great music. Then heading to dinner and back to lounge by the pool some more. My opinion, the best parts of Key West are lost on kids much like Vegas and kids for me.
my favorite things in Key West aren’t really kid friendly. We enjoyed Truman’s Little White House and Hemingway’s House but doubt that kids/teens would. Our fave part though was lounging all morning around our rental’s pool, heading to brunch, and then using our bar cards to spend the bulk of the day bar hopping, day drinking, and listening to great music. Then heading to dinner and back to lounge by the pool some more. My opinion, the best parts of Key West are lost on kids much like Vegas and kids for me.