Thanks for engaging with the adventure! I appreciate the insight.
It's true no explicit hooks direct players to the Kugo basement. It's just as likely that PCs decide to try to run for it, try to fortify the village, or try to escort villagers out of the area. No advice in the module exists for any of those scenarios, which perhaps lead to this module missing the top 8 in the jam.
I also considered their revenge being more targeted! I was originally inspired by "The Fog" where misty ghosts come back to punish the leaders of a town. My tastes veer towards over-the-top, so I opted to push it a bit farther. Restraint might have made for a more interesting story, in this case.