Bittaker and Norris were in Los Angeles, over 600 miles away; not likely.
Sonoma County, where the girls disappeared from, was a rural, low population density area best known for redwood trees and apple orchards. It also had a reputation for a lot of murdered or missing women that are often referred to as the Santa Rosa Hitchhiker Murders. This name is usually limited to six cases that occurred in 1972-73 but these were probably not all committed by the same guy and similar murders continued though the decade.
The high number of murdered and missing women has a lot to do with the influx of people who identified with the "peace and love" sub-culture of the 1960's but preferred the idlic forests of the north coast to the urban areas of the state. Partly as a result of these newcomers to Humboldt Co, hitchhiking became common and was actually a reliable abet dangerous method of transportation. Women particularly found that they could get rides quickly and easily and normally there would be no problem. It is hard to imagine today but in California at the time, thousands of young women routinely relied on hitchhiking to get to work or school. It would be perfectly reasonable for a couple of 14 year olds from a small town in Sonoma Co to hitchhike to a larger town with a mall.
I lived in the San Francisco Bay Area in the 1970's and I was very aware that there were a lot of murdered and missing women at the time. It has become apparent that the Bay Area had disproportionate number of these types of crimes and Sonoma County was a "hot spot". The number of these type of crimes tailed off since then.
I have collect the names of about 50 women who were probable victims of sexual predators in the greater SF Bay Area in the 1970's that are still unsolved. It is likely that there were some serial killers operating that have not yet been identified but I suspect a lot of them were committed by men who stopped after one or two murders and resumed unremarkable lives.
Debra Silva, who I believe has posted on this board has an excellent web site on the Santa Rosa Hitchhiker Murders :
http://www.santarosahitchhikermurders.com/