[FlamesAddiction]

Here are a couple of shots in the dark... Things you may have already thought of.

As someone who travels a lot for work, including to remote areas, it is not that uncommon for me to leave for a job site on a Sunday if I need to start Monday morning, and just spend the night somewhere.... especially if I am expecting a difficult drive. Was he expected to be somewhere Monday morning besides the office? If so, it would be worth checking the roads in those areas.

And sometimes if I am working somewhere, I will re-visit the site on the weekend if I saw some hiking trails or something that I wanted to try, or if I forgot something on site. Was he in the field at all during the last couple of weeks? It might be worth checking.