As they are hitch-hiking, a truck pulls over and you can Bill have to step over the track for the camera dolly.
As they are walking across the desert, there are multiple sets of elephant tracks in the sand, then on the far shot tracks in the sand from the camera crew.
When Jack puts the rental truck into first gear, it starts picking up speed and going well over 70 MPH. But when Jack mistakenly activates the cab lift system, the truck appears to be traveling at about 20 to 15 MPH (when the camera cuts to Jack beginning to scream outside view).
Vera is supposed to be of breeding age. As Kirby had Vera in his act before Jack was born, based on the photos shown to Jack, and Jack being approximately 45 years old and elephants Vera's age when she started performing at around 5 to ten years old, that would make Vera 50 to 55 years of age. 50 is the maximum age an elephant would be able to breed. 70 is the life expectancy of an elephant. These are numbers based on healthy elephants not in captivity or in circuses. Vera would need to be between the ages of 20 to 30 and in good health to be considered for breeding. From the looks of the elephant in the film, Vera is actually only around 27 years old. Bill Murray was born in 1950, Tai the elephant was born in 1968. So, either there is some magical Hollywood film time travel or the writers had such a flimsy premise for a story that they figured the audience would overlook such a big discrepancy.