The Mexico Theory
I keep returning to this. Made a pro/con list for myself to work out thoughts on the matter...
PRO
There are 48 official border crossings from the US to Mexico and TC may have researched the easiest ones to drive through (people on this forum have confirmed sailing right through depending on the checkpoint) as well as which ones had surveillance cameras.
TC only wants to go one way - the known complications of returning north to the US without rock solid ID are irrelevant to him.
Although the FBI has asked Mexico to be on the lookout, their LE is no doubt under-resourced and overwhelmed by the ongoing drug war. Unfortunately, TC and ET are not the news of the day or the priority in Mexico. TC had to have known this ahead of time and wanted to exploit this weak spot. I mean, let's face it, the average Mexican citizen is not on heightened alert for TC and ET.
We know he's been to Mexico (and Panama) before so it isn't a huge culture shock for TC. He also presumably speaks enough Spanish to have served missions there in the past (so perfunctory at minimum).
US dollar lasts longer there.
Can eventually pose as missionary (I have doubts as to how easy this though - some people on this forum have mentioned that you can't just show up to some random village and announce that you're a missionary and that's that).
CON
March 15 sighting in OKC puts them at the border no sooner than March 16 when he's already at fugitive status and the heat was very much on. If he pulled this off, it would have had to have been in an alternate vehicle (not Rogue).
There is always a chance that papers could be asked for, even at known "easy" crossings. Did TC have a backup plan for this scenario? Fake ID's? They are expensive, perhaps prohibitively so, as has previously been pointed out.
Eventually one or both will have to work to survive. How will this happen with limited Spanish? And speaking of the presumed limited Spanish, it can't possibly be good enough to communicate in the more rural regions (i.e. the most likely type of area TC would settle in).
Thoughts?