Spring is glorious here. Fall is beautiful, but it is really hard to time the leaf color, so I would choose Spring over Fall. September can be pretty hot, if you're not a fan of the heat and humidity. Winter is becoming more popular. Dollywood stayed open this year through 1/5/19 and the weather the last couple of weekends was perfect for a visit.
Even though we are local, we use our GPS to avoid some of the traffic when we are in the tourist area. The area around the outlet mall can be really crazy, but there are various routes to stay away from it. Going to Tanger is the running joke with the men in our family. When we really do it, sometimes it isn't so bad, but usually it is a good way to spoil a nice day. They really need a parking garage.
Sheila