Revealing mistake: When the boys drive the car over the gap in the bridge, look at the side view that shows the main jump, watch the front wheels, they lift up in the air unnaturally before the car leaves the ramp. (00:34:00)
Revealing mistake: When Barry is feeding the snake there is some sort of plastic over its mouth. (00:51:00)
Revealing mistake: When they arrive at the University, they drive through a puddle and stop. On the road you can see wet marks for previous takes. It's clear it's from the previous takes as the marks stop exactly where the bus stops. (01:12:50)
Answer: I found what appears to be a full transcript at http://www.tvdance.com/movie-scripts/roadtrip/ although it annoyingly lacks labels on who is speaking each line.
DavidK93