What was the difference between urban and rural areas in 1920?

Same as they are today.

Rural is an out of city environment but you are not in a suburban neighborhood either. So basically like farms.

Urban can come in two subsections.

Urban an Suburban.

Urban is city like New York or Chicago

Suburban is basically the place that houses the people like the president of the HOA and PTA and also the moms that are level 2694 on candy crush.