Ok. I searched the thread. I checked the rule out list on Namus. So here goes. If I did the first two things correctly, this hasn't been suggested. What about Diane Genice Dye? She is believed to have been a runaway and was spotted by a friend several years after her disappearance still in California. Diane is within the age range and perhaps the vast difference in the dates led this to be overlooked.
http://www.charleyproject.org/cases/d/dye_diane.html
http://www.charleyproject.org/cases/d/dye_diane.html