Turns out "Tom Lake" isn't a person, but a place. Was I the only one who initially thought that?
The story is about a woman reminiscing with her grown daughters about her past experiences in summer stock theater and her romance with a fellow actor who went on to become a famous movie star. The plot moves slowly, with the narrative switching back and forth between the past and present.
Not exactly a page-turner, but a sweet and nostalgic tale.