From your link, and looking at this map............
https://www.google.com/maps/d/viewer?mid=zZD4sPiErdd8.kZlkjIsipZPU
Which is excellent by the way. From the gas station to where she was found was about a mile? As stated in the video you provided. Thats a very short distance. Between the gas station, and on the map the number 5 car wash. Which I assume one could clean there car out there. But the carwash is even closer to the gas station than where she was found..........Everything seemed to happend right around there.
I still think she headed that way, towards the number 5 car wash, after driving forward from the pump and exiting the gas station. She may have picked someone up, gave them a ride to where they were headed which was towards the number 5 car wash, and the attack insured not long after they left the gas station and got around the car wash which is closer to the gas station if where she was found was about a mile as stated. Distance from car wash to where found seems even shorter.
I think it all happened right in that area.
I think someone whom was at that gas station that night, knows she may have given someone a ride after getting her gas. But for what ever reason they have not given that information.
I still don't know if she turned left from the pump and headed out or drove forward out of camera range. But i think she did drive forward out of camera range and someone got in and they headed down towards the car wash and her car ended up where found.
Perhaps a sexual assault occurred at the number 5 car-wash. I wonder if during the investigation they were able to determine if any one was at that car wash? Surveillance video perhaps. lighter fluid would have been enough to burn the vehicle. And the way she was parked the fire could have started early while driving, or the killer could have been pouring it in the vehicle and on her while driving and then had her pull into the area where she was found and lit it on fire.............And he could have walked back to the car wash and left the area.
Someone drove by and called 911 to report a fire,
(They didn't see Jessica, she was still inside the car)Or did they? And the killer to perhaps? and then they show up to put it out and see her walking/laying by the car on fire. The killer was gone. He would had to have kept her inside the vehicle until it caught fire and he was sure she was going to burn with the car.
PERHAPS! That is where the gash on her head came from, He knocked her out and set the fire assuming she would die inside and left. But she regain consciousness and was able to make it outside the vehicle and succumbed to her injury's.
If a sexual assault did occur, which with a fire I don't know if they could determine it. Maybe they did in someway. But the killer knew enough about DNA it tried very hard to destroy any evidence, DNA or otherwise, fingerprints etc. He decided to just burn everything including Jessica............This demon probably thought pouring something in her mouth and setting it on fire would destroy any evidence he left behind in her mouth because of a sexual assault....But just guessing on everything i posted.
Add on...I don't think Jessica drove where she was found. I think the killer drove the car there because Jessica was unconscious from being hit in the head. I would bet from the number 5 car wash to where she was found, theirs not another spot to turn in to like where the car was found. I think the killer turned in there and with the intention of driving further inside to ditch the car and her, but the gate was closed so he pulled up under the tree for more coverage, and put it in park so it would not roll back and got out. Pour the accelerate in the car including on Jessica and in her mouth and sat it on fire and walked back to the number 5 car wash and left the area. Jessica regain consciousness was able to exit the vehicle
As far as what was used to start the fire. If not gasoline, and lighter fluid was mentioned, i am thinking more like charcoal lighter fluid. That would be more common to have in ones vehicle in those parts then lighter fluid. I assume it would not be uncommon for someone to carry a small grill and charcoal and fluid around with them in a car or truck for a quick cookout somewhere. fishing home, someones house etc.