Drive, definitely drive!! Most people don't really think they have the time, and lots of times, they probably don't, but if you can do it, jump in the car and cruise down the Overseas Highway for one of the most beautiful drives of your life. The drive is the whole thing...once you get there, there are a ton of things to do, but the drive is most definitely half of the experience. You wouldn't want to take away from gorgeous sites to be had on the extensive drive down to
Key West, for sure, and go to some of the stops on the way. If you have time, take it all in. That's what it's all about!