And when they are pulling into a "wild" campground, both people would be excited and looking around to choose a place. I can see sleeping in the back, even with no windows on a long haul on the freeway. Maybe she was just "sick" from some physical abuse, and staying in the back, voluntarily or not. And then on the night between 26-27 he finished her off, and took time to get her out of there under a few short hours of darkness? Or even walked her out there if she was groggy and hurt, then completed it out there. (Still not believing the restaurant story on the 27th, but open to seeing proof)