But a determined group of outsiders recently made the trek. They were leading forensic investigators searching for new evidence of death - clues pointing to possible decades-old clandestine graves.
And the results of just-completed followup tests suggest bodies could indeed be lying beneath the parched ground. The test findings - described in detail to The Associated Press, which had accompanied the site search - conclude there are two likely clandestine grave sites at Barker Ranch, and one additional site that merits further investigation.
Next step, the ad hoc investigators urge: Dig.
For years, rumors have swirled about other possible Manson family victims - hitchhikers who visited them at the ranch and were not seen again, runaways who drifted into the camp then fell out of favor.
The same jailhouse confessions that helped investigators initially connect the band of misfits living in the Panamint Mountains to the gruesome killings that terrorized Los Angeles hinted at other deaths. Manson follower Susan Atkins boasted to her cell mate on November 1, 1969, that there were "three people out in the desert that they done in." Other stories surfaced. In the absence of bodies, they were forgotten.
"We prosecuted Manson and the family for all the murders we could prove. But you know, could he have killed someone else? Possibly. Could another member of the family have killed someone? Sure," said Steve Kay, a former deputy district attorney.
Last month, equipped with cutting-edge forensic technology, the investigators assembled in the ghost town of Ballarat for a 20-mile ride in all-terrain vehicles to the ranch.
The team included two national lab researchers carrying instruments to detect chemical markers of human decomposition, a police investigator with a cadaver-seeking dog, and an anthropologist armed with a magnetic resonance reader.
Also in the group were a woman whose life was forever marked by the cult's brutal murder of her pregnant sister, and a gold prospector who was once Manson's closest neighbor and remains intimate with the sharp creases of the Panamints.
Prospector Emmett Harder guided the expedition.
He had a claim on Manley peak, one of the jagged points looming over Barker Ranch, while the Manson family camped out there in the late 1960s. He shared dinner with the band at times, and gave the men work.
During one of these visits he heard Manson say, "We're not hippies; we're here to get away from the troubles of the world."
Later, Harder would learn more about the cult leader's belief that the end of the world, which he called "Helter Skelter," was near - and Manson's conviction that through murder, he had a role to play in accelerating that chaotic time.
For the last 5 miles of the rugged gravel road from Ballarat, the route tilts sharply upward as it enters narrow Goler Wash.
"The family's plan was to make this impassable - you can see how you could do that here," said Sgt. Paul Dostie, a police detective and dog handler from the town of Mammoth Lakes, pointing to the boulders that protrude like bones from the canyon walls. Any of them could be rolled into the wash, blocking passage.
Barker Ranch was one of several hideouts used by Manson and his followers. The killings that launched the cult onto national newspapers had been orchestrated from Spahn Ranch, a former Western movie set that served as backdrop to episodes of "Bonanza" and "The Lone Ranger."
It was to Spahn that the killers initially retreated after the 1969 murders of Gary Hinman on July 31; Sharon Tate, Jay Sebring, Voytek Frykowski, Abigail Folger and Steven Parent on Aug. 9; and Leno and Rosemary LaBianca on Aug. 10.
This was to signal the start of the apocalyptic race war that Manson told his followers would pit blacks against whites. He preached that they would emerge from the desert at the end and rule over the survivors.
But a daybreak raid on Spahn Ranch on Aug. 16 by Los Angeles sheriff's deputies looking for car thieves netted 26 arrests. All were released a few days later on a technicality - a misdated warrant - but Spahn was no longer safe.
Barker Ranch was where Manson withdrew in those last, frenzied days.
Retracing his steps nearly four decades later, the search group stopped at the dilapidated house. From the porch, the view was clear for miles, broken only by the long twisted stems of creosote bushes and knee-high bunches of desert rabbitbrush.
"After the murder, my mom became a shell of herself," said Debra Tate, who was 17 when her sister, actress Sharon Tate, was killed. Her younger sister Patti was 11. "I filled in at home, as best I could."
Debra Tate's mother, Doris Tate, emerged from years of depression when she heard that a Manson family member was seeking parole.
She gathered 350,000 signatures, helping keep the murderer in prison. She also lobbied successfully to change state law to ensure the rights of victims' family members to make statements during sentencing and parole hearings.
Doris Tate died in 1992. Her youngest daughter, Patti, followed in 2000. Now Debra Tate, 10 years younger than the glamorous, doe-eyed Sharon, whom she grew up admiring, attends the parole hearings alone.
"My mother specifically asked me to carry on," she said, adding, "It's my life."
She has given herself two tasks, she said: making sure her sister's killers never go free, and helping other families find the peace that has eluded her.
"If there are bodies here," she said at the ranch, "we need to find them and send them home."
About 100 yards behind the house, Dostie readied his trained dog, Buster, for the search.
"Go find Fred!" Dostie said, releasing the dog on the command that sends him searching for human remains.
The dog bounded away, zigzagging over the terrain. Then he lay down in a depression in the ground, quivering, ears upright. Buster looked at his trainer and emitted a high-pitched whine.
"He's alerting," Dostie said, throwing the dog his reward and planting a flag on the site.
Meanwhile, Arpad Vass and Marc Wise, senior researchers from Tennessee's Oak Ridge National Laboratory, were readying the first of the instruments they'd brought, capable of chemically detecting evidence of decades-old human bodies. It was a hand-held device shaped like a gun.
"It's a crude sniffer," said Vass. "It gives us a quick indication of areas we want to come back to."
The machine detects fluorinated hydrocarbon compounds, one of the approximately 400 types of volatile organic compounds emitted by human bodies during decomposition. Focusing on these compounds is important because Vass believes they're formed as the fluoride added to urban drinking water is released after death.
Their presence helps differentiate a human bone from bones from wild animals, explained Vass, who has spent years developing a decomposition odor database using bodies donated to the Oak Ridge lab.
The instrument beeped at regular intervals. As it approached the ground, the beeping accelerated until it was a steady stream of sound.
"That's impressive," said Wise, a senior researcher at Oak Ridge specializing in environmental analytical chemistry. Vass agreed.
Using a thin, 3-foot long probe, Vass tested the soil in the area. It slid into the ground without much effort.
"Undisturbed soil isn't this easy to probe," he said.
"The loose soil area is roughly like this," he said, using the tip of the instrument to draw a long oval on the ground. "It's about three feet deep."
"We need to do an IR," he said, turning to Wise.
He was calling for the next piece of machinery - larger and heavier, but more specific. It could be calibrated to detect different compounds, using technology known as infrared spectroscopy to "read" a particular molecule's profile.
"We're getting the highest hits here, where the ground is soft," said Wise. "There's definitely something down there," he said. "We just can't know yet exactly what until we dig.
"Or who," said Vass.
The men crouched close to the ground, gathering three samples of dirt from each area of interest for further analysis using more finely tuned lab equipment that could not be brought into the field.
The group broke for lunch. Dostie shared bread and cold cuts in front of the ranch house where Manson was finally arrested, in October 1969, after being found crammed in a bathroom cabinet.
Afterward, Daniel Larson took up his part of the investigation. An archaeologist at California State University, Long Beach, Larson has used Ground Penetrating Radar and a magnetometer - an instrument that can peer 12 feet into the ground - in archaeological work and to help find burial sites.
At Barker Ranch, he took 5,327 readings of the ground at the suspect site, stopping every four inches within a 26-by-20-foot grid, looking for discrepancies that indicated earth had been moved.
"What I'm looking for is the pit, not the bones," he explained.
He'll have to return later to use the Ground Penetrating Radar. The soil still held some moisture from recent storms, and that could disturb the results.
Watching the scientists do their work, Harder spoke of his memories of the Manson clan - the churlish, armed young men, the pretty girls with blank, doll-like expressions.
"I didn't feel real easy around them," he said. "They picked up all kinds of people - hitchhikers and stuff."
He particularly remembers two teenage runaways who escaped the ranch, then stopped at a nearby mining camp for food. They had enough fear in them to make it out of the rugged mountains barefoot, said Harder.
They turned themselves in to the California Highway Patrol at the mouth of Anvil Springs Canyon - booked as Stephanie Jean Schram, 17, a runaway from Anaheim, and Kathryn Rene Lutesinger, 17, a runaway from Los Angeles, on Oct. 10, 1969.
"Both females stated that they were attempting to run away from 'Charlie' the leader of the 'family' and that they were afraid of their lives," read the CHP report.
Their fear was well-founded. Following the police raid on Spahn Ranch in August, Manson and the family killed ranch hand Donald "Shorty" Shea for "snitching" and buried him out there.
That body wasn't found until more than eight years later.
"I dug it up myself" about a quarter-mile behind the ranch house, said Sgt. Bill Gleason, a now-retired homicide investigator with the Los Angeles Sheriff's Department.
"There were rumors of other deaths, minors killed out in Death Valley," said Gleason, who took part in the original Spahn Ranch raid. "We just didn't have anything concrete to link to the Manson family."
The runaway girls didn't know how close they'd come to becoming another one of these rumors.
The day they turned themselves in, CHP officers headed to Barker Ranch for the first of what would be two car theft raids.
On their way, they arrested two men - booked as Gary Milton Tufts and Randy J. Mourglea - whom they found asleep at the mouth of Goler Wash, a sawed-off shotgun between them. They were from Barker Ranch, CHP said.
When told of the arrests, both girls told officers they believed the armed men were sent "to stop them from walking away," according to CHP's report.
Were others less lucky when they tried to escape?
Vass said that, considering the quantity and the types of markers of human decomposition found, the cadaver dog's response, and the probing exercise, he found enough evidence to warrant further testing at a deeper level and a full-scale excavation at Barker Ranch, according to the report he issued to law enforcement.
"I'd recommend a dig, excavate the sites," said Dostie, who reviewed the report.
But if a body is found on the Barker Ranch, then what?
The likelihood of a new prosecution appears slim. Locating remains would be just the first step, said Patrick Sequeira, the Los Angeles County deputy district attorney who has been in charge of the Manson family parole hearings since Kay's retirement.
"You have to tie them to someone who has disappeared, and there were a lot of people floating in and out of the family environment who were runaways, or hiding out," he said.
Then investigators would have to find out who killed them, where, and who could testify, he said.
The Manson family members currently in prison are already serving life sentences - the maximum penalty allowed at the time the crimes were committed.
Still, Sequeira did not discourage the efforts of the crime scene re-investigators. "I'd love to see them put something together," he said.