I've finished designing a few buildings for the map.
The plan right now is to do all the texturing & lighting in Photoshop, so the Illustrator artwork is mostly lines with limited color. The colors still need adjustment, something I'll edit when I move into Photoshop.
I've been doing a lot of experiments with pattern brushes & the appearance palette (to get multiple strokes on the same path) in Illustrator, to see about streamlining the workflow of making so many buildings. You can see the results of my efforts on the wall building (left). The low wall around the house is also a stroke style. Right now it looks like the buildings themselves will have to be drawn manually, although I have a brush to make variable-length buildings (so that the roof texture carries along) too.