Ok, here it goes. This isn't as easy as it looks...
I've tried to find pictures that are true to the era of the book. This is what a block of houses/shops would have looked like. Notice the driveway to the inner courtyard.
This picture is of a row of shops, on a quiet street, imagine they faced a row of similar buildings and shop fronts.These are fairly upkept, the middle one could use a fresh coat of paint...
In this last picture there are two houses on the same block. Imagine a lane way, or a driveway was in between the two houses instead of a fence and bushes, with a courtyard tucked in behind. Imagine that the house to the right of the main one pictured, on the other side of the laneway(if it existed), there was a decrepit scary house with no windows, dark and dreary and a few bums sleeping on the front stoop. (doorway and stair area)
The author is giving directions to the house. So, he describes the quiet well kept street of businesses, and on that quiet street there is a laneway, two buildings from the end of the block, and at that point, that very spot is the house in question.
Hope this helps.