As for the trip itself, I'm not very sure what there would be since I haven't travelled farther than Virginia for the most part, but there are some amazing places to see in Nashville, one of which being the fucking beautiful countryside that stretches across the southern part of Nasvhille, farms, hills, etc. As for Nashville itself, the coolest place in my book would be to go see Jack White's record building, Third Man Records - it's a beautiful place to see and they have a bunch of White Stripes memorabilia sold only there. It's also a photo boutique as well, so definitely check it out.
And of course, PLEASE visit Grimey's records. It's one of the greatest record shops in that city - they even have musicians like Elvis Costello play in the store during record releases and such.