A major issue I have with any theory is the distance. Presuming that Caitlyn got into trouble/foul play in Bogata...I cannot recall a case where the the perp(s) abandoned the car 50 miles away, and the missing person was nowhere to be found. That would require a second car and a two-person team, one to follow the other.
The general area where the car was found doesn't really make sense either, as the river flow isn't very fast, and was found within a week.
In other cases, the perp drives the vehicle (or pays someone) to a chop shop of some kind to get rid of it. (like the Toni Sharpless case, someone mailed a letter to the P.I alleging that he/she was paid $5,000 to drive to a chop shop.)
If the perp felt rushed or panicked, I could seem them hastily abandoning the car in a nearby location and poorly covered. Driving such a distance, however, would suggest there was a plan? but what kind of plan.
All speculative/opinion.