I can really see a benefit to walking out of there, (no accomplice needed), but I see many drawbacks as well. I don't think it is clear from LE statements. They were covering their bases asking if anyone saw anyone walking out of there.
Here's the thing, it should have been close to daylight/dusk when the vehicle was dumped. People are getting off of work and heading home. If this person is walking he has to go alittle over 2 miles just to get to the intersecting at Squilchuck. Granted there aren't many homes on Pitcher the first half-mile of his walk/jog.
Idea: Is our suspect in good enough shape to jog?
From intersecting at Squilchuck who knows how much farther but the roads only get busier. Yet, as far as we know, LE never got a tip from ANYONE who said they saw someone walking along the road. That hints towards him getting a ride out of the canyon.
It's up in the air for me.