I strongly recommend you take a trip to the Florida Keys and Key West while youre in South Florida. Key West is like a tropical Cape Cod...haven to many artists and writers such as Ernest Hewingway, Robert Frost and many other ones! Even though, Key West is not renowned for its beaches, there are many other things to do there. Its an historic town, so lots of things to see in the Old Town district, scuba diving or snorkelling (they have the only reef barrier in North America!), sunset celebration in Mallory Square and having the best key lime pie in the World!
Its easy to get there by either driving, flying or boating. Its about 3 hours drive by car, 4-5 hours by greyhound and it costs about $50 round trip/person.