It wouldn't surprise me if there is no "real" answer, even from Michael Smith. Some songs just start from a few images, or a brief half-remembered scene, and take on a life of their own. I once started out writing a song about my grandparents, and by the middle of the second verse it turned out to be about two people I'd never known, one of whom has Alzheimer's--which my grandparents never had--and only "comes alive" when she dances with her husband. In that case, the half-remembered scene was from the movie "Harry and Tonto," and I didn't even know if it could even happen outside of the movies. Then, when I sang the song for the first time at the Seattle Song Circle, a friend came up to me afterwards and said, "That's exactly what happened to my mother." As I said, some songs just take on a life of their own...

Aloha,
Mark