Mystery solved! Thank you, Joe and Jim. I read through the fifteen page autobiography, and found mention of the Boston Common concert that I heard. I also found mention of most of the songs I remember hearing at it. I see that the song I called "It's Then I Start Thinking of You" (from the last line of each verse) is really titled "It's Great to be Independent" (from the first line of the chorus.)

Instead of returning to her home in Massachusetts, she was a Canadian singer on her way to visit relatives in Rowley, Massachusetts. Rowley is next to Byfield, where the snuff was made, so it fits.

I'll have to look up what other information I can find about Vera Johnson. Thanks again!