I am still plugging away on Richard Kaczynski's biography of Aleister Crowley, Perdurabo, and there's a passage where Crowley seems to anticipate the idea of reality tunnels and of switching from one reality to another.
Chapter Eight, "Singer of Strange and Obscene Gods," relates that Crowley wrote a book that was a "collection of devotional poems to the Virgin Mary" (although it had decidedly unpious hidden messages). But it says that it's just as well the hidden messages were not noticed, because "Crowley's intent was not to blaspheme" and that he was attempting to write from the mindset of a good Catholic.
The book quotes Crowley as saying, "I do not see why I should be confined to one life. How can one hope to understand the world if one persists in regarding it from the conning tower of one's own personality?"