Given my past experience with this sort of hike, I would drive to Georgia, park at The Hiker Hostel, get their shuttle to the start, and start hiking north. Then, whenever I was ready to get off the trail, work out my shuttle at that time and place. There are several reasons for this:
1. You might need to get off early. This will cost you a second shuttle back to your car, which can get expensive. (Ask me how I know this. Er, twice.
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2. For me, it prevents that "gotta make miles" feeling and lets me take the hike on its own terms. If I have to be at a certain point on a certain day, it makes feel like I have to rush.
Getting even a long shuttle on fairly short notice isn't really that difficult, especially if you've talked with some shuttle providers ahead of time. The Hiker Hostel folks are terrific, and if you get far enough north, the folks at The Hike Inn near Fontana are also great. The drives are not that long -- what took you two weeks to hike can be driven in 3-4 hours