That's what I was thinking, perhaps with a return to Mordentshire, but not focused on a body switching Jekyll and Hyde machine. Although you could suggest the device where players switch between a character in the new adventure and a character in CoS whenever they take a long rest as an option. I don't recall the original adventure mentioned why it was called Gryphon Hill (I assume it was a meta reference to Griffin, AKA the Invisible Man). Although with the de Toro Frankenstein doing the rounds, maybe a return to Lamordia would be in order? Curse of Mordenhiem also works as a title. Perhaps even more directly calls out Hammer.Yeah, I would just take the Gryphon Hill name and make a new adventure. Van Richten's had a ton of settings that demanded to be played in, and coming up with a new adventure -- or even a whole anthology of them -- wouldn't be hard.