This "collage" is terrible, so I'm not sure how much use it will be. But what it looks like to me is that just before the spot where the SUV is abandoned, the vista is pretty wide open on both sides.
The same thing is true of I-10 just after that location.
There's this one spot, right about where the SUV is parked, where on both sides of I-10 you have a rise in the embankment (more so one the west bound side). And if the SUV was parked just past the two lamps, there might have been a sense, whether accurate or not, of being obscured. Maybe not. Only someone driving this route at night would be able to tell.
Once you pass the Oak Valley Parkway exit, there's not much reason to exit off I-10, until the Sandlewood Road exit 8 miles later. (And that might be significant.)
IF (big IF HERE!!!!!) this was an abduction. And whoever carried this out wants to leave the SUV in a place where they are least likely to draw attention to themselves. And they are least likely to be caught on surveillance---this might not be a bad spot.
I-10 then travels on to San Bernardino (the city) and beyond. But if I were going to plaster another area with Missing Person's Posters, I'd take a shot at that Sandlewood exit in Calimesa, and all the shops, restaurants and gas stations there.
Apologies in advance for crappy pics. Nothing takes the place of being there.
