I've also thought about whoever she hung out with/confided in right before she disappeared. She was a student at Hernando High at the time. It sounds like she and her friend Laurel hadn't seen each other since the end of the 78/79 school year (I think one of the girls changed schools?) Did she have other close friends from school? Were Tammy and Kevin still dating? It sounds like it. But he seems to have thought that she was somewhere local. Maybe we could find the Facebook site for Hernando High School for that time period, and ask around? If she were 16 in Fall 1979, sounds like she'd have been 1981 graduating class?
If she spent a lot of time on the CB radio, and also chatting with truckers at the truck stop where she worked, could she have possibly shared her plans with someone? Like, where she was headed, and possibly who with? I guess that goes back to trucker forums. Do truckers (and retired truckers) still use CB's? One of my uncles was a trucker, based in Florida, at the time. Unfortunately, he passed away a few years ago -- sure would like to pick his brain.