I agree for the most part. First if the Walmart visit was just a diversion, it would have been very risky. What if someone in the Walmart store recognized them. They would have been caught right on the spot. I think the only reason they would have risked going to Walmart is if they need supplies.
That said, if I was running from LE, I would not go in a straight line. Because I would expect LE to be looking for me along that route. If my destination was West, I would go North or South as quickly as possible, then I would turn West and travel on back roads. Because LE wouldn't be actively looking for me to be traveling that direction. I also wouldn't travel straight West and and then double back and travel straight East. Because that would take me right back through the center of the search area. Which would be too risky.
I still think they are camping in the backcountry someplace near Tennessee in an area that TC is familiar with. But as time goes on with no sightings, I think there is an increased chance that maybe they continued West to some location, or maybe they circled around in some other direction.