Take a calling card that will work at pay phones and hotels, especially if you are likely to get off the interstate and out of the range of cell phone signals.
Since your trip is likely to include a fair amount of driving, pack some tunes. Depending on your destination, pick up some classic country, bluegrass, blues, or Elvis albums to get you in the mood. And I never get on the road without a small cooler and some lunch supplies, especially if I may be on the back roads for awhile.
If you’re planning on spending time in the Great Smoky Mountains [1], be sure to pack rain gear and several layers of clothes, including a jacket or sweater—even in the summer. If you think you may do some hiking, bring good boots, a backpack, and a trails map.
Links:
[1] http://www.moon.com/destinations/tennessee/great-smoky-mountains