You mentioned doing the topography later but, depending on how drastic the elevation changes will be, the topography would affect the way the roads are laid out. Just looking at this map I do not see any areas where there are obvious changes in elevation based on the roads except perhaps the Arewood (more curving roads perhaps around hills). As such, I would suspect the area to be really flat, with little topographical change.
Not sure if this is the type of feedback that you wanted but hope it helps.