In this case, I thought the real story was Circe's time with Odysseus, but now I'm wondering if this melancholy part I'm in now, near the end, was the real story: what happens after Telegonus goes to meet his father Odysseus and inadvertently kills him.

It's true I can't think of a lot of contemporary treatments of the Telegony and that's neat. It does sound a little like the author got the ratio wrong, though, if you had to slog through an entire novel first.