Ah! Not to worry, I found the solution.

The island of
Sifnos is not marked on the map, and is a tiny island between
Kea and Piperi - so it's easy to miss. Once you hit its shores, though, the quest moves forward.
I think I dimly recall that there used to be an icon showing a fortress on that island? But that might just be my old-ish brain thinking of things that I saw when I played this game back in 1998.
Never mind... thanks for letting me ramble.

Please feel free to delete this thread if it's taking up space... thanks!
P.S. I included the words "SHP installer" in the title because, IIRC, I used an SHP installer to install and play this game? But again, I might have simply forgotten.
