The Dwimmermount megadungeon is a massive beast. I’ve played in an online Roll20 Dwimmermount campaign, and it’s on my list of “adventures that I’d like to run someday”. Dwimmermount’s history and background is tightly tied to its campaign setting, but I think I might be able to make it work with Operation Unfathomable.
If I were to run Dwimmermount, I’d need to change some things. The implied setting starts out as pretty close to “vanilla fantasy” which becomes stranger the deeper you delve. I’d prefer to make things a lot weirder from the start, by combining it explicitly with Operation Unfathomable as well as taking ideas from Devilmount and Anomalous Subsurface Environment.
The Odious Uplands / Mastodonia would lie directly north of the Dwimmermount Wilderness Map, with Fort Enterprise (from Operation Unfathomable) located in Winterburg, north of the Wintertops. Dolmenwood and the Hill Cantons would lie somewhere vaguely to the east.
I’m just going to leave this page here as a placeholder, if the opportunity ever arises to run Unfathomable Dwimmermount.