My preference for someone starting out in Tennessee would be the fixed coop, not the tractor. A tractor needs to be moved regularly, every few days, a lot of work and requires constant attention. That can be an additional problem in winter if you get snow. Operating and maintaining a fixed facility is much easier.Honestly I feel paralyzed by information overload, so it would be so helpful just know what you prefer.
I personally do not believe not following those rigid guidelines for size of a coop and run people are quoting will lead to the downfall of western civilization. Most of the time those guidelines of 4 sq ft per bird in the coop and 10 in the run are overkill, more than you need, though each situation is unique.
I know it is even more information, but if you follow the link in my signature below you can see some to the things I think are way more important than a rigid adherence to certain numbers.