The Other Side is the first piece in the Vandermeers' wonderful Weird Compendium, where they published an excerpt about a strange sleeping sickness that comes over the town of Pearl (a sort of amalgamation of Central European cities), and gives the town over to the animals for a time while all of the characters sleep. It is a wonderfully bizarre little fantasy, but it left me expecting something very different from the rest of the novel, which I finally just read...
So "Pearl" is not a fictionalized Vienna or something, it is actually deep in Central Asia where the unnamed narrator's friend from high school has purchased some pristine high altitude wilderness upon which to construct an artist's utopia called Dreamland. There is some unnecessary and kind of stupid detail about how the guy originally came upon the insane fortune of land and money (by saving a Chinese noble's kid from drowning), which I guess is how people had to justify their fantastical stories back in the day before Lovecraft finally told everyone to "never explain anything".

I remember reading somewhere that the illustrations came first, being intended for Meyrink's Golem, but the contract fizzled out, and so Kubin decided to write a story to justify the images instead. Inclined to think it's true. Interesting novel for specific parts, as you say, but I do agree, not the strongest on the whole as a living text.