I was looking back at the isotope analysis for Beth and reflecting on the probability that she'd lived in Eastern Tennessee for the last 5-10 years of her life after emigrating from Europe. Western/Central Europe is mentioned which is terribly vague but she looks distinctly Mediterranean in her most recent recon so I'd suggest she's perhaps unlikely to be Dutch/German etc. Perhaps Italian or Balkan? South of France? Czech?
Now, I know nothing about Eastern Tennessee (I live in the UK) so I had a little browse on Wikipedia and recognized a couple of city names. I was surprised to learn how small the population of these cities are; well under 200k people. I also noted that the demographics suggest that there probably aren't large established immigrant communities there. For example, only about 1% of the population is Roman Catholic. Now, it strikes me that a young immigrant girl from Europe, only settled a few years, most likely from a Mediterranean country is very probably Catholic. Possibly Orthodox Christian if she was from the Balkans. Possibly Jewish. She would have been quite unusual in Chattanooga or Knoxville in the 70s. She probably went to high school in the US at least, perhaps even her entire school career. So either she was a rare immigrant student struggling to fit in at public school, in which case, I'd imagine she'd be pretty memorable or she went to Catholic School perhaps.
Eastern Tennessee is a fair distance from Pennsylvania. I wonder how much coverage the case got back then since it wasn't local? Do you think that yearbooks from East Tennessee Catholic schools from the mid-70s might be worth looking into? Perhaps there are some alumni associations that could be contacted? Are there any resettlement charities/community organizations in Eastern Tennessee for specific ethnic groups from Europe, like an Italian community centre or Jewish welfare society?
This all assumes the isotope data is accurate though.
