There is also construction south of Franklin TN where they are widening the road and putting in a new bridge.
If you want to avoid Nashville, get off I-65 at exit 53, Cave City KY. Take 90 to Glasgow, KY. Then take 31E/231 to Lebanon, TN. Get on I-40 for about three miles to 840 and then get back on I-40 south of Franklin.
I live in Murfreesboro, TN and take this route frequently to head north on I-65 to avoid Nashville traffic. Good two lane roads most of the way and a nice scenic drive both on two lane and last 20 miles of 840