I have a ranch in Los Gatos Canyon near Coalinga, Ca. There are the remains of an old homesteaders cabin on the lower part of the ranch. About 300yds away, just off my ranch, there are the remains of another old cabin... a much nicer one originally and remnants of the old stone chimney can still be seen.
Now the history:
Charlie Acres died, well, not sure when.... 60's? Maybe the early 70's. He lived 100yrs +. He was the known 'historian' for this area having lived there his entire life. I met him a few times. Charlie lived maybe 10 miles from my ranch. Most of the families who own ranches in this area have owned the land since the 1800's.
Charlie told the story that Joaquin's girlfriend was the daughter of the settler who owned the cabin just off my ranch, and visited her often. Joaquin Murietta mostly robbed the gold seekers far north of this area and across the central valley in the Sierra Nevada Mountains. He hid out in my area. This is all pretty much 'known' fact.
As with all old outlaws/bandits 'legends' sprung up.... the following is NOT fact, or at least can't be proven... but believed by nearly all who live in the area around my ranch. Lot of the gold and money Joaquin stole was never recovered so the 'legend' is that it's buried in the 3 Rocks area. (3 Rocks is the predominant mountain near my ranch). True? Who knows?
When I was in college in Coalinga I had a friend nicknamed "Goose"... can't remember his real name if I ever knew it. Goose and some of his friends were exploring near 3 Rocks in the late 60's and discovered a cave. Inside the cave they have some old firearms and donated them to the Coalinga museum... still on exhibit today. The firearms were traced back to Joaquin's era but never linked to Joaquin himself.
This area is extremely rough and arid. You could pretty much hide anything and it would probably never be found.