Best way to get a jump on what's happening that weekend is to probably check the listings of the local altweekly -
Nashville Scene
... if I were going, I'd try to find out if some of my favorite Nashville-based musicians, like Larry Carlton, Vic Wooten, Bela Fleck, Phil Keaggy, Jeff Coffin, Kenny Anderson, etc., were playing locally. I'd also check out the Country Music Hall of Fame & Museum.
And don't forget about
http://www.bluebirdcafe.com/ - legendary place for up and coming singers and songwriters