I used to build replicas of city blocks using boxes or bulding blocks for the buildings, TinkerToys for the power lines, and printout paper for the roads (I would then use markers to paint the lines on the roads). Back in the 80s the printout paper I'm talking about came in spools that could be rolled out and torn off accordingly. I would use Hot Wheels cars as the vehicles and so I built the models roughly to scale with the Hot Wheels cars. Thus my models would sometimes take up the majority of a room. I would even build the warning sirens by Using the TinkerToys as a pole and using yellow or orange construction paper to build the horn part. I also would use small paper plates to build those large satellite TV dishes that were common in the 80s. According to my mom, I would often beg to be driven around the particular block that I was building so that I could get a better perspective of how the various objects were laid out. I would then get down eye-level with my model and make sure my pieces were arranged as close to scale as possible.
Once I was about 7, though, my younger brother had begun to walk around and could not be prevented from getting into and f!*%ing up my models. So I eventually saw the futility of spending long hours building and gravitated to drawing maps. After my brothers got old enough to be drawn into my "world," though, I sort of went back to building models to a degree and would sometimes build simpler environments to use for us to play in. Legos were big, as well as Hot Wheels cars and a (very) large electric race track that we rearranged to use for roads.