There is no way to go straight at the turn. The road ends and you can only turn left or right.
Once you get on 79 it does not fork. It looks like they would have had to turn on to Chihuahua Valley road. It's a deliberate right turn and leads to dirt back roads by the scout camp.
But there is no way to know why they did. There was nothing back there if they needed help. And had they gone just a couple miles up they would have found a gas station on 79.
I'm a little late to this discussion but know the area well and will answer very frankly. I own a Jeep Wrangler equipped for offroad jaunts and I've been to the LCIR many times.
For the life of me I can't figure out why they ended up where they were, out in LCIR. There must be a lot more to the story than anyone is saying. Here's why.
First, there is no "fork in the road" at the junction of CA-79 and Camino San Ignacio. It is a very clear right turn from a maintained highway onto a paved but rougher residential road. Even if their nav system said the road passed through, this would have been a very deliberate turn away from the correct route.
Second, after 5 miles or so they pass through an open barrier, with speed bumps, saying they are entering an Indian Reservation, which is private property and by which permission is necessary to pass. It is not manned 24/7, but the signs are clear. They ignored these signs, or were too disoriented to notice them.
Third, after another few miles, many of which are confusing, they would have ended up on a one-lane dirt road that led into the mountains. Surely anyone thinking clearly would have sensed they were getting into trouble.
Fourth, after another few miles, they would have been traveling along roads barely passable for passenger cars, with no lights or buildings or any signs of human habitation. This too would have been a warning sign.
Fifth, the maps published showing their route are incorrect. There are two ways to get to what is called the "Helo Pad" or the intersection with the road to the Boy Scout camp, and they did not take the route further east. That one is barely passable with a Jeep Wrangler. The journalist who claimed to have "verified the route" did not do a very good job.
Sixth, the route from the Helo Pad to the place where they were found is a very sandy and rough route. I am shocked that they even got that far. I drive that in 4WD low. Another warning sign to a thoughtful driver. And, they most definitely strayed from the instructions of that flawed GPS nav system.
The only story that makes sense is this. The Knutsons followed a very flawed GPS nav system, continually ignoring very clear signs and other information that they were headed for trouble, that led them to the Helo Pad (4-way intersection) where four dirt roads meet. They turned left (north), once there, on their way to the Scout camp and 1/2 mile further along they came to the permanently closed gate. They turned around, went back to the Helo Pad, and thought that the eastward direction might give them a way around the gate; also foolish because the road they now drove on was more perilous than any of the previous. They drove another 1/2 mile before sliding down a steep grade and marooning their car. They were only six miles from human habitation, and using their nav system should have been able to plot out that route before heading out. The route would not have been hard to walk because it is not steep. Even at their age it was a walk of six hours, perhaps a full day. Yet, perhaps because of their age, or general fear and disorientation, they were unable to accomplish such.
So, and again I feel a need to be candid here, the Knutsons made a host of bad decisions before getting themselves in their predicament. Yes, the nav system might have told them the road went through to the Scout camp. No one in their right mind would have chosen that route, rather than CA-79 to CA-371, unless he said, "honey, let's take a longer route that looks rough but will give us a little adventure." Either that or he was too elderly to use a nav system properly. And no one in their right mind, after the nav system led them astray, would head off on perilous unknown roads for further short cuts.
I am not blaming the victims, I am trying to just add a little balance and candor to this discussion.