Note that the last segment of I-485 around Charlotte (linking I-85 and I-77, through Huntersville) is currently under construction, with completion expected by end of this year. So the Huntersville site won't be too far out of the way for I-85 travelers, soon.
I actually just got an email back from Huntersville. I don't believe it's there. Wherever they're going next, I would image that the permit is in place or close to it seeing how much work is left in Macon.
"There have been some talks about potential charging stations in our region, but we’re not aware of any related to Tesla at this time. That said, that is something we’re certainly willing to discuss, should the opportunity arise."
I think the location will be off I-85 instead of I-77. That seems like the more popular route, especially whats been built out to date. I think Concord, NC would be a good option as they have an outlet mall there is a well which has partnered with Tesla in the past.