It seems extremely odd that Kathleen Johns was taken on a two hour journey around Tracy, California by an extremely dangerous individual, yet managed to escape into a field possibly as little as 400 meters from her abandoned car. In other words, she just happened to escape from the perpetrator's vehicle at the point she began her two hour abduction.
According to Robert Graysmith, who told her story in his Zodiac book. Kathleen Johns 'scooped up Jennifer and jumped from the car, dashed across the road, and leapt into an irrigation ditch surrounded by tall grass in the middle of a field. "It was all wine vineyard with a little gully and I just laid as flat as I could."
As Gian Quasar stated in his excellent article "Johns made many mistakes in her retelling of the events that prove damning to her own initial story let alone the legend she later adopted. One very significant one is that she said when she escaped from “The ZODIAC” into the fields she plainly described them as vineyards (Graysmith). The only vineyards around 132 are at Bird Road. They are still there today. The only thing Johns has ever been able to clearly describe is the immediate area of where she initially stopped. No other place." link.
Kathleen Johns stated in the Robert Graysmith book "I couldn't handle it anymore, so I decided the next time he came to one of those Hollywood stops-you know- not a complete stop-that he made at the different stop signs, I was going to jump out." Suddenly the car came to a halt. The man had inadvertently driven up a freeway offramp.' [A short section of road which allows vehicles to enter or exit a highway; also called entrance ramp or highway ramp]. Somewhere in the location shown in the link above or image below. Here we have the likelihood of an intersection 'offramp' and vineyard in close proximity to one another.
The police report stated "Mrs Johns then got to a roadway or highway, this part is not clear to undersigned or to the Stanislaus Deputy, Mr Lovett, but finally did get back on highway or near Highway 132, where she was given a ride by some people from Missouri." Not being clear or able to remember you were rescued a mere stone's throw from your vehicle, could be useful in an abduction claim.
Some people suggested this may be an insurance job, by burning her vehicle. This seems a hell of a lot of effort, 368 miles from her San Bernardino residence, to claim such a payout. Is it possible this was something far more creative, designed for publicity, and feeding into the Zodiac Killer story for gain. There may be three possibilities, assuming Kathleen Johns didn't disable and destroy her own vehicle, particularly bearing in mind she was pregnant with a small child.
 Kathleen Johns traveled with another adult, who drove her near to, or by Patterson Police Station (where she just happened to spot a picture of Zodiac who resembled her abductor), then drove the vehicle back to the predetermined location, disabled the vehicle and set it alight, taking the car keys with them. The police never recovered the vehicle's keys.
 Kathleen Johns was rescued by the good Samaritan and taken to Patterson Police Station, while the person who traveled with her remained near the vehicle. Once Kathleen had been rescued, the accomplice grabbed the car keys, then disabled and set fire to the vehicle.
 Kathleen Johns was telling the truth, and she truly is a victim here.
But we have to consider the story told in Robert Graysmith's book: "Kathleen gathered up Jennifer and got into the man's car. Just as they were pulling out, she noticed that the lights to her car were still on and remembered that the keys were still in the ignition. The man smiled, went back to her car, snapped off the lights, and pocketed the keys." Despite him being friendly at this juncture, she failed to ask for her keys?
Kathleen Johns was seven months pregnant with a 10 month-old child. Heavily pregnant women have to visit the toilet regularly, not withstanding the fact, she was driving a 1957 Chevrolet station wagon she described in the Graysmith book as junky: "The man (supposedly Zodiac) started flashing his lights off and on. My car was such a clunker I figured something was wrong with it."
From San Bernardino to Bird Road is 368 miles. It would take just over 6 hours traveling non-stop at 60 mph to reach Bird Road. That would place Kathleen Johns being pulled over at around 10.00 pm. But she was driving a "clunky" 1957 Chevrolet station wagon and was pregnant with a small child in tow. It likely took longer. We will allow an hour extra (7 hours journey time), which give or take a few minutes, would mean that an approximate 4.00 pm departure time, has her traveling towards Bird Road around 11.15 pm.
However, did the truth come out when relaxed and being interviewed by Robert Graysmith at a later date, when she was far more detailed : "Kathleen Johns bundled up her ten month-old daughter, Jennifer, and left her home in San Bernardino at 7.00 pm for the trip to Petaluma, a small dairy-farming community, where her sick mother lived. It was easier to travel at night while the baby slept."
If this was the true time, it would make the abduction claim virtually impossible. A 368 mile journey with such a vehicle, in her condition, could only be achieved in just over 4 hours (7.00 pm to 11.15 pm), if you were traveling at 86 mph non-stop. But if you took 7 hours, as described above, then you would arrive at Bird Road on Highway 132 at around 2.00 am, the approximate time she was 'rescued' and taken to Patterson Police Station, making the abduction story now fiction.
She is either driven by her accomplice to Patterson Police Department (20-30 minute journey), who drove the vehicle back, or she is picked up by the good Samaritan from Missouri and taken to the police department. Either way, she would now arrive at the Patterson Police Station at 2.30 am. The time recorded by Sergeant Charles J McNatt.