He was being assigned to the Army Evaluation Center Fire Support Evaluation Directorate.
He was an arty officer so this makes sense.
His studies in Monterey at the Naval Post Graduate School were done in order to secure his Master's of Science degree, with distinction, in Systems Acquisition Management.
He must've had some information with him that the Army didnt want falling into the wrong hands...probably nothing more.
If he were a high mucky muck spook then I doubt he would've been "driving across the country" with sensitive documents...they would've flown him on a "Tower Air" jet or some other MAC flight.
He probably just had some fire support documentation that was a little too high speed to allow it to remain out in the open.
That's probably it. The Army could easilly track his trip and when reports of the collapse came out through Emergency Management they knew he wasn't just stopping for coffee. What doesn't make sense is stiffing the local businesses when he could have as easilly operated upfront if that's what happened. He should have reported to the State Emergency Management on scene who are well trained to deal with such matters and no one's the wiser. By operating this way he sure drew a lot more attention to himself than most would want on offical business.