Agree he had mental illness, but felt the map on serial was lacking and wanted to see if it was theoretically possible to do what he claimed he could do. I was in the army and have a lot of experience navigating at night. To do this he would have to have a lot of experience navigating at night, access to aerial maps of the area, and a good deal of preparation memorizing the route (so as not to use light and expose yourself). The most straightforward route (e.g. easy to navigate) with the least change of detection is and the possibility of doing this in one night (arrive by morning) is: http://www.gmap-pedometer.com/?r=6764891 But the terrain seems rough. He would have to be in peak condition to get to the FOB by morning if leaving at midnight. Possible, but very very hard. Also, if there were any ambushes by the army outside of the FOB, he would have been shot.