I've been driving I75, I65, I71, I74 all my life (well, as long as I can remember in 62 years), and never a problem. Even I64, and I77 in West Virginia isn't so bad. As stated above, it's all Interstate, fairly gentle climbs and fairly gently down-hills. Now, if you want more of a challenge, drive I40 from Knoxville, TN to Ashville, NC. It's not so much the actual road, it's the crazy semi-truck drivers that are frightening on I-40.