Memphis TN to Clarksville TN

I40 out of Memphis, to about Brownsville,(west of Jackson. US 79 to Clarksville. Good road, will be mostly two lane, but a lot less traffic, and the shortest route. Mostly flat land. Over toward Dickson and US13, you will be in the hills, lot of up and down and twisty two lane. We are in Lexington, and run 79 from McKinzie east a lot. Quite a bit of new four lane that way also. Get a NEW Tennessee map, Google, Garmin, and all the rest are way behind actual roads and bypasses in that area. Been several years since we went to Clarksville, but I don't remember any problems.