Great Smoky Mountains National Park
Even our most popular national parks empty out in the autumn, partly because the kids are back to school. But just as the parks don't shut down, neither do the educational opportunities. The Great Smoky Mountains Institute at Tremont offers various fall activities including photography workshops and guided hikes with an expert naturalist.
For those who prefer to leave the learning to the classroom, this sprawling, 521,000-acre protected land offers hundreds of miles of hiking trails and roads, horseback riding and fly fishing.
Read Peter's guide to his favorite national parks
And if the great outdoors isn't really your thing, nearby towns such as Gatlinburg and Pigeon Forge, Tennessee, have every kitschy tourist amenity and family attraction known to man—and more. If you're in the mood for adventure, try the Zorb, a New Zealand–style thrill ride that involves being thrown down a hill in a giant rolling ball. You have to see it to believe it.