BBMLilibet, you are a super sleuth, for sure! Thanks for doing all that brain work to try and figure out possible timelines for Jenny's journey just before she disappeared. You are awesome.
I had forgotten that I already posted a similar post before (the notebook post) . Now I get to use the embarrassed emoticon face, lol. :blushing: If that info is still true (or partially true) then maybe the shopkeeper family is in or near Juchitan. I had been thinking they were in Oaxaca. Ah, well...as you said, we just don't have enough of the right details to put together a scenario that is most likely.
If the truck with Jenny as a passenger was picked up at the Pemex we were looking at on Hwy 185, would the truck have made a stop in Juchitan or merely passed through/by? If just passing by, I don't know if many people would have taken notice of the truck. A large double-trailer type of truck seems like the kind that only goes from one warehouse to another, doesn't it? Where did the truck originate, and what was its destination. I know we don't know the answer, but I wonder if the PI knows that much.
No need to blush! Your earlier post was great. We know next to nothing and it's very annoying.

If the Corona driver was going the opposite way from Cancun (but still going there), he would have traveled south on 185 and caught 190 eastbound before reaching Juchitan. Then he could have taken 145D north to 180, the highway that eventually gets to Cancun. I'm not sure of the road conditions, but he could have branched off of 145D onto 187 to get to 180. If he'd gone north on 185 he would have hit 180, but apparently he was avoiding a roadblock. Maybe rosesfromangels has some insight on the roads. I remember reading that truckers don't like going through Chiapas because it's a winding route with drop offs.
https://www.google.com/maps/@17.4267253,-94.0859906,8z