To take in national parks, sightseers must usually backpack, hike, or drive on endless two-lane roads. It's not every day you can glide over the park in a luxurious yacht, but that's exactly what the Key Largo Princess does. Aboard the 70-foot glass-bottom yacht, sightseers gaze down upon the John Pennekamp Coral Reef State Park, the only underwater state park in the United States and the only park to get Smokey the Bear's unconditional safety approval. Along the way, the yacht sails over the cerulean swells of the Atlantic, offering panoramic views of the Florida Keys. When they're not oohing and aahing over bright tropical fish and an abundance of living coral, passengers can feel the breeze on the deck or relax in the air-conditioned indoor salon with a snack from the sandwich bar.
Spend a day cruising around the briny blue in a variety of specialized watercrafts. Each is equipped with GPS and Sirius satellite radio, devices that will periodically gain self-awareness and argue with each other. This will keep you on track on an oceanic highway with no roads, while occupying your ears with noises other than seductive sirens and dolphin clicks. The radios are iPod ready, enabling you to provide your own soundtrack if the one beaming from outer space is too alien. PonTunes provides life jackets for everyone except minors, so either remember to bring preservers for your kids, or conveniently forget to bring your kids.