Thank You!!!
Thank You!!!
You will (and apparently have) confused some people talking and one direction or another entering/leaving TN/NC because the trail (especially thru GSMNP) follows the TN/NC border.
But as others have stated, head south from I40 and you immediately enter Great Smoky Mountains National Park. You would not be able to register as a thru hiker in GSMNP and so you would have to get a permit and reserve a spot at each campsite you plan to camp at (and you can only camp at the designated campsites). No way of knowing now if the park service will continue with the relaxed social distancing rules. If the return to normal rules, you would be required to sleep in the shelter (as all but one campsite along the AT in GSMNP is a shelter).
As others have said, it is uphill, both ways. Going south, I don't recall exactly, but it is around 10 or 15 miles of almost all uphill before it starts to mix in some downhill to.
I would seriously consider finding a way to hike the other direction and end at I-40. But it's your hike, so do what you prefer.
If you choose to start in GSMNP, it's generally easier to start at Newfound Gap rather than Clingman's Dome. Newfound Gap has parking right at the trail crossing. If you park at Clingman's Dome, you have to walk uphill around 500' to get to the trail, and then it will be mostly downhill to Newfound Gap. If you have a week, starting at Clingman's Dome will give you some extra mileage. If you want to hike even further, the next road crossing for the AT is Fontana Dam all the way on the other side of the park. Obviously a car can get you to both Newfound Gap and Clingman's Dome parking lots, but it is a more time consuming drive to get to either of them compared to the I-40 crossing.
I section hiked GSMNP several years ago in mid-April- I had gotten permits for all the shelters I was going to stay at but there were so many thru hikers if you weren't at the shelter early enough there was no room when you got there and lots of others tenting around- ended up sleeping on the ground under the over hang rather than squeeze in. You could probably tent as well if that is the case. I heard another hiker with a permit asked people to move out and was not received well and a ridge runner did not intervene. Also confirming it was very cold at night and had some snow as well.