I can't find Fang's article in his list. He does mostly Victorville - but yes, I would think that someone like him would be interested (he does a lot of crime writing for Victorville, Apple Valley and Hesperia).
Thing is, they easily could have gone back in that direction - it's pretty in some areas and on the way to other places of desert beauty (although...Victorville itself is not really a tourist destination). We go out to Vasquez Rocks for fun and I recommend it to international tourists all the time.
Victorville is a sizable community compared to many others out there, and so lots of eyes on the road who would be looking (although a bit late, now).
If foul play is involved, then the area around the Salton Sea is almost literally No Man's Land (certainly No Woman's Land, IMO) and filled with places a truck could (temporarily) disappear.
See how the land kind of takes a dip before the Sea,
here? There are other places where the sagebrush is higher, as well. But just driving down to the low shoreline of the Salton Sea (with its small dunes above) would hide a truck until someone decided to pay attention and report it.
This is taken from an actual street in Salton Sea Beach. As you can see, in this particular neighborhood, while there is a street (unpaved) and...some buildings (do the 360 turn) this is typical of a "populated" spot out there. Between this place and the town of Salton City lie 10 miles of...nothing. Well, there are some
signs of life here and there. In this example, there's an intersection - and the roads go on for miles (and other similar intersections intersect and go on for miles, too).
Heading more over to Julian, we go past an "airport/town." This is
Ocotillo Airport. The whole airport is invisible, behind a low ridge. The entire area is filled with small dunes, large dunes and long, low ridges. The airport is small, of course - but my point is that I want to provide context for saying "nothing out there."