Actually, taking a closer look at Tesla's new 2015 map, it looks like they're planning superchargers in or near Statesville NC, Charleston WV, and Morgantown WV... with the caveat that their future maps can have a large margin of error, both for location and timing.
If the map is accurate, then only the ~225 mile leg from Statesville to Charleston would be difficult (especially in winter). But if the I-81 corridor eventually includes a supercharger near the overlap with I-77 (i.e. Wytheville or Fort Chiswell), then Charlotte-Pittsburgh would be easy.
No guarantees of course, and I have zero inside information. But I'd be optimistic that your direct route will be supercharged within a couple years. If you drive this route frequently (I don't), I'd recommend sending specific site suggestions directly to Tesla's supercharger team:
Supercharging