Hixson used to be a separate town NW of Chatanooga but hard to see the boundaries now.
Of the towns you have mentioned I would pick the Chattanooga area. The Tenn river runs through town and you are only a couple of hours away from the Great Smoky Mts.
We have talked about moving to Tenn but so far we haven't found an in tact farm in the Townsend area that would support 4 families.
I lived in Memphis for the last 2 years I was in the service and the summers were bad. In June the breeze quit and it was just hot until Sept., plus it is flat. I didn't mind since I was only 4 1/2 hr from home home, not the 2000 miles away in San Diego.
Larry