Is this an acceptable way in terms of performance to go about building roads or am i missing something? i am new to large level design, i just want to get the basic lay of the town down so i can run around and start prototyping
When you are finished with all of the pieces just select all of them, go into Window-Developer tools-Merge actors. That will merge all of the road pieces into one static object with one material, instead of 30 and 30 individual draw calls.
The only thing I can suggest is to not build the roads first, this will limit your creation into boxes you made and will end up dealing with a pattern rather than a creative real town.
Start with roads and building at the same time, then change the pattern into something else, different looking houses leading to different road and path style, then leading to a warehouse or station or huge streets or , or, or …etc
Better use photos of real cities as references and modify while using your own imagination if you want some realistic design.