South florida. What to do on the way down..... Im driving from orlando to key west. As i have kids i will be?

stopping off on the way down there. Maybe overnight. What is a good stop off point. What is good to see on the way down. Miami? Fort Lauderdale? Any good beaches? I saw a gator farm near a prison. Where is that? Any tips would be good. The trip will be in feb next year after the 15th