Halton Woman's news coverage, 1978
The original Hamilton Spectator article about the still-unidentified woman found in Halton in 1978 gives some critical detail to the case. Two key facts mentioned in the story that aren't in later police missing persons listings are: a) that the Halton Woman was found in advanced stages of decomposition (which means she may have been there for a long time), and b) that no foul play was suspected (this may have changed in the pathologist's report, but that report is unavailable).
Once these case files are attained it will be interesting to see what the pathologist ruled as time and cause of death. It could help in finding her friends and loved ones with a more precise timeline.