There aren't mountains anywhere near North or South Padre Island. They are shown in the back ground in some of the scenes showing the boat piers. There are sand dunes in the area but they aren't that large and they aren't by the pier. Also, South Padre and Corpus Christi doesn't look very tropical.
When Reid and Morgan first asked questions to Adam, they met him on the roof, where he likes to spend time. Yet, when the team is looking for him none of them thinks of looking there. Madison has to tell Rossi about it.
When Reid and Morgan are talking at the end about Tobias Hankel (from the season 2 episodes "The Big Game" and "Revelations"), Morgan mentions that "He drugged and tortured you for two days." Reid relieves Tobias of any wrongdoing saying, "No, it was the persona of his father who did those things to me." It was in fact the persona of Tobias, not the father, who drugged Reid and ultimately gave him an addiction, in order to ease the pain of being tortured.
At the very beginning, we see that Amanda is supposedly being videotaped, as she is on camera. Yet there is no indication that the camera is recording (or that it even has a tape in it) when we see the screen, and when Reid appears, there are no cables coming out of it (so it's not connected to a computer). Therefore, they are not recording anything and the camera is redundant.