[DF] Ideas for the Astral plane

[Stone Dog]

You could do worse than to check out GURPS Cabal for the hermetic cosmology. It is mainly 3ed, but the rules aren't very hard to translate.

I am taking the concept of the astral plane as a sort of intermediate plane that allows access to other planes so that a person from the material world could travel to Olympus or Asgard from the astral plane

Check. The astral connects to basically everywhere and if you wander far enough you can find just about anything that you need to find, or want to avoid.

...Elder Things... Maybe because the astral plane is much less ordered than the others?

The Elder Things have a beachhead at the Shining Citadel of the Ythoghu.

It probably isn't that the astral is less ordered as we think about it. If the material plane is where all the threads come together to make a tapestry, the astral is where the loom is full of potential. It still has rules and the Things haven't warped the Citadel to their needs, but they have a genuine presence where they don't on the Material.

astral plane also contains dreams and dreamworlds as well as concepts of higher thought.

Check. All of these things!