The Appalachian Trail leads from Springer Mountain, in Georgia, to Katahdin, in Maine. It's 2,167.1 miles from end to end, with the halfway point around Gardners, Pennsylvania. It's beautiful everywhere, and due to being well traveled, not that tough or dangerous. It takes around five months, depending on your pace. With maildrops and equipment, it is best to prepare ahead, even if you're not a thruhiker. There are many books on the subject, reading one of them is worthwhile. Whatever you do, getting information from the Appalachian Trail
Conference is definitely encouraged.