Since Travis and Hunter are driving from L.A. to Houston, they would take I-10 going from west to east. When they arrive in Houston, the view of downtown is from I-45, which runs north/south from Dallas to Galveston.
While traveling to LA, Walt tells Travis that Hunter will be eight in January. However, while in Houston on the 5th November, Hunter tells Travis he'll already be eight by the same time the following month.
Travis and his brother check into a small motel on their first night, where we see a dresser with an ugly lamp sitting on top. After Travis runs off, they continue down the road and stay in a larger hotel, where we see the same dresser and light.
When Hunter calls Walt and Anne from a payphone in San Bernadino, he is supposed to be calling collect (Travis is shown instructing him briefly on how to do it). However, when we cut to Walt answering the telephone at home, he is immediately on the line with Hunter and is never asked if he would care to accept the charges for a collect call.
When Walt is looking at the photo booth pictures of Travis in his car, he shakes out a cigarette from a Marlboro soft pack and throws the pack on the dash. In the OTS shot of the photo strip, the cigarette pack on the dash is a hard box.
When Walt gets Travis to a motel at the beginning and wants to buy him new clothes, they compare feet and decide that Travis wears one size bigger than Walt. Later, at Walt's house, Travis asks to wear Walter's old boots and puts them on and they fit fine.
As Travis is entering the whorehouse, two figures appear in the window above the door and seem to look at the camera. One of them waves (as if acknowledging being waved out of the scene) before leaving the window.
When Travis shows Walt and Hunter the picture of the vacant lot he bought in Paris, Texas, the photograph shows a desert landscape. Paris, Texas is located near the forests of East Texas, hundreds of miles from any desert.
Travis and Hunter make a phone call from a Texaco gas station in San Bernardino. In the background we see the road-side dinosaurs, which are in Cabazon California, closer to Palm Springs. Not a big mistake, but a distance of some 40 miles.
When Travis and Hunter are following the red Chevrolet from a downtown bank, they merge onto US HWY 59 northbound, just south of interstate 45 and north of the HWY 288 interchange with US HWY 59. After a few moments pass the next shot shows them approaching the HWY 59 and HWY 288 interchange (going northbound on HWY 59). This interchange is located about 1/2 mile south of the onramp they took in the previous shot so there is no way they would have been able to approach this interchange going north on HWY 59 had they taken the northbound onramp in the previous shot.