1-40 between Knoxville and Nashville - Friday Dinner
It's definitely not fine dining, but there is every chain restaurant known to man right off the interstate in Cookeville (about 1 1/2 hours from Nashville). Also extremely not fancy is the Bean Pot in Crossville (an hour from Knoxville). I haven't eaten there, but every time I've been inside for a pitstop it has smelled wonderful.
Eating in Knoxville (try Litton's) early on or in Nashville if you can hold out might be your best bet.