Its typically a great time time to be there. Like most places, temperatures and precip can vary. But I would say October is about perfect for Linville Gorge and most other NC trips. Temps will likely be above or near freezing at night and maybe 60s during the day. Bugs likely won't be a problem. October is probably the lowest precipitation month for that area, but rains seem to always be possible there.
Its a pretty area. I hope you enjoy it.