And considering that SC was not in the habit of doing nice things for her, wouldn't she be highly suspicious of him offering to put some gas in her car? He could easily have siphoned some from his vehicle, because he didn't necessarily tell her that his truck was stuck. I think he told her that he wanted to talk about the baby. But if he had worked out the "stuck truck" alibi ahead of time, he would have had to conceal his truck from others to make that stick. I think he said Kurt Kaiser gave him a ride to work and he met SC on the road, not at his house. I will go re-listen to that testimony in a bit.
I imagine both of them in her vehicle because I don't think he wanted to leave any evidence in his. No matter how well his truck was detailed, blood stains are stubborn. I also imagine her incapacitated in some way before or during the drive - drugged, knocked cold... Interesting that there were zip ties near the bloody jeans.
But I can also entertain Peter's theory that she never left Haiku alive, but her cell phone and Nala did. Hopefully, will soon know if any microscopic evidence was found in SC's truck. Would Charli's 4Runner have made it down that dirt road? Hers was not lifted.