Take some field trips, and examine the small towns you see. Take a notebook and camera along, and visit Norway, Fairview, Springville, Lisbon, Ely, Fairfax, Walton, Atkins, and Newhall, and see what is there, and try to find out what used to be there. Don't just examine the commercial sections, either; explore the residential areas. How close together are the buildings? How old are they? Take a pencil and notebook, and a camera, and take lots of pictures and make lots of notes for future study. Go to the library, and get some books surveying urban development. Every town developed the way it did for a reason. Try to find out what the reasons were, and how they affected development. Then use that as a model for how your town developed. A very small town will have one commercial center; a larger one will have a primary commercial center, and a couple secondary ones. If the town was founded before the railroad came through, the commercial center may very likely be away from the train station. ON the other hand, if the town was founded by the railroad, or after it came through, the original commercial center would likely have been around the railroad station. But it's possible urban blight in that area might have resulted in that area now being a secondary commercial center, with the primary one being some place else, perhaps around the big box store at the edge of town.
Remember that very often the view seen from the railroad is the back of buildings, not the front, and pay as much attention to the views in the alleys as you do to the views from the street.
One thing you may find, is that in old cities and towns, the area immediately around the commercial center is occupied by larger dwellings of the merchant class, with smaller dwellings around those.
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