Machen, Arthur: A Fragment of Life, v.1, 9 January 2009.
 

Arthur Machen (1863–1947)
A Fragment of Life

A novella.
By day a young man and his wife lead a prosaic life in London. By night, he dreams of a mysterious wood. But which is the true reality?

The Machen Society webpage comments:
“Around the end of the 1890s Machen began to be interested in the healing potential of a more orthodox mysticism. His novella "A Fragment of Life" chronicles the life of Edward Darnell, who begins the tale as a suburb-dwelling clerk but makes an inward and outward journey towards mysticism and the land of his birth, Wales.”
http://www.machensoc.demon.co.uk/machwork.html

Or just read it as Narnia for adults.