“Could it be he is heading over to visit the troops and his itinerary is a secret?”
That sounds plausible. Is the SC National Guard deployed at present?
A few years back I remember when Cheney visited some South Pacific nations. One Freeper was hysterical because Cheney's plane was reported to be in an unscheduled place that the person thought was out of place for a return trip to DC. The Poster yammered on posting almost hysterically for nearly a whole day about the missing Cheney a if alliens had taken him up. Turns out he was headed for Iraq and the government didn't inform that Freeper of his every move. The unannounced ahead of time out of route stop the press picked up on was obviously for fuel.
A man deer hunting in the winter or trout fishing in the summer can be difficult to reach even though several may be privy to the general area. Two-three hours from Atlanta driving can put a person into such areas. Being in a state vehicle though he can likely be reached and have access to Emerengency Management Communications in an instant.
Our governments are set up to function with or without any one person being present.