A large national park on the border of Tennessee and North Carolina, it includes a wide range of features and potential activities.
Must-see areas include Cade's Cove, a mountain valley that is maintained as it was in the 1920's, when the residents were moved out to create the park. Plan on spending most of a day taking the auto tour through Cade's Cove -- this park has the greatest number of visitors of any park in the national park system, and most of them want to see Cade's Cove. The auto tour route is a single-lane one-way road that circles the valley, and usually the traffic is bumper-to-bumper. There is no good way to escape the traffic.
Another good drive is the Roaring Fork motor nature trail, which begins and ends in Gatlinburg. You can also drive across the park to Cherokee, North Carolina with a stop at Clingman's Dome, the highest point in Tennessee. There are many hiking trails in the park as well -- the Applachian trail also crosses the park.