The Portable Wargame or Panic on the streets of Berlin 1919

Half term has arrived and along with it a new enthusiasm for the hobby is on the scene.Many thanks for your advice in response to my previous post.I have gone for a new project-The German Revolution of 1919 through the lens of the portable wargames modern rules.
As the combat was essentially an urban one with small units, I have been thinking of how to depict this on the tabletop.I tried to jot ideas down in my notebook-

The blue area represents buildings to be made by blocks of wood or cardboard .

However a trip to the Heriot Watt University Borders Campus (to let my middle daughter go to an Open Day) yesterday availed me of the chance to buy some foam board at the college shop. I mocked up the potential city scape today as seen above.It is only an attempt to get some idea of how things look and play.Thank goodness for the old faithful cereal packet to experiment upon.

The figures used are Peter Pig  Freikorps and Spartacists made from SCW figures.I have some sailors and a tank on order but am looking for  ideas for armoured cars and lorries etc.

As ever I would be grateful for your ideas/suggestions about urban combat and how to make scenery for such a project.