The Lair of the Witch Queen makes some broad implications about the world in which it is set, but what does the world of your Witch Queen look like? New classes? New races? New magics? New minions? New Witch Queens? Entirely new worlds of adventure?
Use the CC-licensed In the Lair of the Witch Queen rules (available here, for free) to create your own worlds of adventure, expounding upon those rules or brutally eviscerating them and reconstructing something new from their remains!