As one astute poster in this thread previously observed: the "abandoned" Chevy Astro Van, found in a wheat field, had been carefully secured -- locked even -- but with no trace of Sara inside (except maybe her cellphone which had been turned off). Something is definitely rotten in Denmark.
If the van was left in a very rural area, do you think anyone would notice or be bothered enough by it being there for 5 hours to call police?
PURE SPECULATION ONLY ON MY PART: The only one who'd be bothered enough would be the indfividual who left it there. That person would want to get the ball rolling on the "missing woman." Notice that all reports of "the phone call" that reported the suspicious vehicle (thus setting the wheels in motion that something had gone awry with this young woman) has not been attributed to any particular individual, or even an "anonymous" caller. MY OPINION ONLY
It has not been reported that anyone actually saw her leave for work.
It has been reported that she was wearing her blue Walmart employee vest and that everything was A-ok when she left for work that morning. For our purposes, the eyewitness details are lacking by whomever actually saw Sara that morning before she left for work allegedly driving the white Chevy Astro van. To my knowledge, there have been no media interviews (or public appearances) with either her father or her stepmother. We don't have much to work with.
Has anyone taken a polygraph?
When I strung these posts together along with relevant comments you used in the posts, I felt I got very good flavor of what you're saying, that being that the people closest to the person have the best opportunity to cause them harm. They have access to them and to the knowledge of what they would be expected to do (what they would wear, when they would leave, even what route they would take.) That's why that scenario is looked at so closely by LE as I am sure it is being looked at now. Maybe that's why we don't sleuth that theory here at Websleuths , because it is so closely investigated. It could be I'm still reading you wrong; set me straight if that's the case.