Yeah, rather tired of the 'cloak and dagger' and the rumor mill grinding away.
IMO...it was obviously a one-time Spfld event. Not committed by a vagrant (no car), not a hat wearing peeping Tom (peepers peep), not a biker or a wanna-be biker (they shoot each other), wasn't a drug deal gone bad (typically tempers flare then blood flows asap), not motivated by money ($750 isn't chump change)....
Fact: I have the June 19, 1992 newspaper article turns outthe Apco guy looked at and spoke directly to Sherrill. He remembers distinctly because he typically had approx only 10 customers a night.
It also has another 'snarky' comment made by Kathy Kirby concerning Sherrill. (Hello! Sherrill is missing, likely dead, and Kirby's criticizing .... and nobody thinks that's weird?)
I'll get it posted asap. Stay tuned.
So here is a very viable theory that goes hand in hand with what you posted here.
Lets say that the Apco Sighting by the convenient store clerk was accurate.
That means something brought Sherrill out of her house in the middle of the night looking for her daughter Susie.
How would Sherrill know something was wrong and that she needed to go out in the middle of the night looking for her.
Did Susie make a phone call from the Apco Station to her house left a frantic message for her mother who didn't pick the phone up before Susie left a message.
Does this account for the erased message on Sherrill's phone?
Does this also account for the posibility that something happened at one of the parties that placed Susie in a situation of trying to escape from someone or someones.
Did she even make it home that night, and does this account for the purses being lined up in an unusual spot where they normally wouldn't have been, as well as the police stating that the house was perfect, too perfect (or something very close to that affect), lending potential credence to a staged crime scene.
Did Ms Kirby provide an alibi for her daughter by stating that she heard what she heard regarding the girls talking on the porch about going to Susies house, when it was June and she had a house full of company, and one would think would have had the A/C on and her window closed.
Why did they Walk according to Mr. Appley from the Joy residence they had returned to, to Ms Kirby's house which wasn't right around the corner as they told the story, but according to Google Maps, over 1-mile away.
And Mr. Appleby stated he watched them drive away. Well, Janelle said she then went into her house for the night. So what did Shane do, walk back to the Joy house to retrieve his jeep, on a dark country road, over 1-mile away, in the middle of the night? Why didn't one of the girls give him a ride back to his jeep. Why didn't they take his Jeep to Janelles house also, instead of walking over 1-mile.
None of their story's make sense. However if the Apco Clerk did indeed see Sherrill, someone must have called her to let her know there was trouble. How else or why else would she have known or been out looking for Susie at that time of the night.
I'm not convinced that they ever made it back to Sherrill's house, regardless of the cars and clothes being found there the next day.