Would a crossover D&D Campaign with Steven King's Dark Tower be a good setting story-wise?
Imagine your party discovers an evil plot being orchestrated by a being known as The Crimson King, and must travel across The Cosmos as well as Alternate Time-lines and even to The Parallel-Plane of Earth. They must stop The Were-Spider from destroying all of creation, No Matter The Cost!
You encounter various Fiends, Monstrosities and Aberrations along the way as well as beings and monsters from Stephen-Kings Mythos as well and even The Gun-Slinger.
This starts in DnD setting and enters StephenKing-verse