(I'm a day behind so if this has already been addressed, my apologies.)
While I agree that some rustic site makes a lot of sense, I think you're misreading a piece of evidence that has you focused on the wrong rustic sites, maybe.
You've picked sites near the 121/Custer intersection. But, there's not really a reason to focus there, to the exclusion of other places, and to some extent there's a reason NOT to.
When EA was noted as being past that 121/Custer area, it was because he was flying NE up the 121 tollroad and passed the toll-collecting sensor at that point as he traveled. That doesn't hint at travel on those side areas at Custer/121, and in fact somewhat points against it. Obviously he could have traveled further NE, exited, and then doubled back, but is it likely?
The fact he triggered that toll collection only means he left the road somewhere NE of that point, not that he stopped at CUster/121. And once he passed that collector, it's the last one, so he could have kept going and veered off anywhere past that point. Here's the map.
https://www.ntta.org/roadsprojects/existroad/Documents/SRT_Project Map_050112.pdf