First, I question the haz mat trucker's story. With what he has said happened, what was happening that he took so seriously that he perceived a threat and changed locations and called 911. A supposed police officer flashed a badge. The story he gives doesn't give any indication that the alleged police officer was trying to stop him, and it would be illegal for him not to stop for police. So I guess I am a little confused about the trucker's story as it has been related.
If it is true however, I am wondering. What if it is unrelated to Stacy? DrewP has had a lot of money in the past and there have been questions as to where he acquired that money. Some truckers get into the drug scene. Is it possible that DrewP was into some drug running scheme and this was a pick up or drop off? Flashing a badge during the exchange would be pretty risky if it was his day off, but would provide good cover if there was a problem.
If Stacy's disappearance was planned, then DrewP could have been there to try to find a trucker to carry a "package" out of state. I have always said that if you wanted to hide a murder and make sure the body would never be found, you would take the body out of state. For example, no one would ever connect a body found in say Calif. with a missing person in Ill. But getting the body from the truck into some hiding place would be a problem. Unless DrewP knew someone who was willing and trust worthy out of state to do the pick up. And between the computer and the phone records, police should have been able to pick up on that.