Lisa is on my list as well, along with many others. I think your theory is very plausible given her age regarding the marriage. It's so frustrating when there is so little information.
But I do think this is a very good one for comparison if there is enough information to include or exclude her. Might be worth someone attempting to get in touch with her daughter if possible.
Laurie Allison Smith
The National Missing and Unidentified Persons System (NamUs) is high on my list as well.
I think it's incredibly likely she is not from the immediate area. Unless there is a specific reason she was not reported as a missing person (perhaps an immigrant, trafficked from another country, or an adult "runaway" ie: left an abusive relationship, etc.)
The jewelry is just so specific, I can't let it go. It had to belong to someone who is older or relatively well-off..