I realize that this might be way out there........but................could it be possible that Mackenzie's death was purely accidental...............but her injuries came about as a result of somebody trying to transport her somewhere to dispose of her remains.......on a dirt bike... respectfully snipped
I've thought of the dirt bike/motorcycle idea before. Here's my thoughts about a bike:
Assuming she was the one driving up Pitcher Canyon, to me taking only her cell phone and debit card, (and car keys?), at the end of a paved road might be something someone who was about to hop on the back of bike might do. At the same time, lots of woman don't bother with the purse thing and just carry those items on them all the time anyway.
Would be interested to know if MC usually liked to keep her purse with her or not? If so, it might indict she left her car, (whenever that was), unwillingly. I'm thinking she was just usually the type not to use the purse much, because I see no use for the killer(s) to leave her purse in the car but take out debt card. So she likely had them on her all the time so we don't have any indication she left her car willingly or not. Also meaning it wouldn't support the dirt bike/motorcycle idea in Pitcher Canyon.
As for the wounds being caused by fall from motorcycle, (on accident), I just don't see moving a body that way as a viable explanation. I suppose if the unknown scene number 2 is somewhere nearby the Crescent Bar vacant house, I could give the idea a very distant... maybe? Moving a body by motorcycle I would think nearly impossible. Either way, none of us would really know-know about the wounds until the autopsy results are released or they have solid enough information to personally believe otherwise.
I think we would all like to believe the death was some tragic accident, with the person so scared they attempted to cover it up. But from the horribleness of how I understand the body to have been left at CB, I think I would just be happy to hear those things were all done after death.