Swannanoa is more of a participatory thing than an entertainment venue, but there's a lot of fine music there. Madison County, right next door, has been and is home to many traditional musicians. Try this website:
"http://www.madisoncounty-nc.com/info/events.html" (How come I can never make a blue clicky?). For advance reading, if you're into that sort of thing, I'd recommend three books: "The French Broad" by Wilma Dykeman (it's a river, not a woman), "Minstrel of the Appalachians" by Loyal Jones (bio of Bascom Lamar Lunsford), and "The Kingdom of Madison" by Manyl Wade Wellman.