A local library might have older maps that can be a very useful resource, even a street map from a bygone era. Local newspapers on microfilm can be a tremendous resource for prototype research.
Another resource that can be of considerable value to a modeler who is trying to replicate a particular prototype scene and era is the old fashioned city directory. Unlike a phone book which is alphabetical, a city directory goes street by street number by number and gives the name of the person or business. Some of the really old ones give the occupation of the breadwinner. Best of all they tended to mention railroad tracks as landmarks, so if a track came between street numbers that would be mentioned., Sometimes one learns of track spurs that you never dreamed existed by seeing this. They tended to come out every few years, not annually as a rule. Many had maps in the back that are also useful.
This can become almost an enjoyable and even poignant exercise in local archeology. Get enough of these directories and you can trace a family living in a home for 40 years and then no longer; a business changing hands -- or even changing type of business -- rapidly or slowly. A given street number that is currently a vacant lot might have been a house or store or machine shop back in the day. Comparing a 1928 City Directory to one from 1935 and seeing the many businesses disappear can be almost heartbreaking.
Specific example: I model 1967-69. I was excited to be given clear photos of a 1962 train wreck at a certain crossing that I will be modeling and the photos showed that the gas station (long since torn down but I remember it) was a Shell station. I assumed not much would change in five or seven years. Ah but the mid 1960s city directories show that shortly thereafter it became a Pure oil station. And knowing that enabled me to finally make out the word "Pure" on a very blurred Brownie camera snap shot I had taken around 1966 of a C&NW passenger train.
So much for all the Shell signs I had carefully collected. Fortunately a fellow Forum member here had some spare Pure signs he sent me.
Dave Nelson