Thank you so far.
Would you like to have walls in a pseude-3D-style? They can be cut away if you don't need them...

I used Photoshop, 3dsmax and InDesign.

@torstan
You are right that the printer friendly layer is some sort of blurry and overexposed (that is because it is not just a grayscale image of the color layers).
I think i will replace it with a hand-drawn (ols-school/Heroquest) version. I am currently working on another test tile where you can see the effect...