We don't have to guess what this looks like. We can just look at pre-car neighborhoods in the U.S, which were a lot more dense than modern suburbs, but not necessarily extremely dense. The largest U.S. cities in 1920 included places like St. Louis, Cleveland, Pittsburgh, and Baltimore [0], each of which have several neighborhoods with a gentle mix of single-family homes alongside two-, three-, and four-family flats and traditional corner stores.

If you let neighborhoods develop organically, then this is what you get.

[0] https://www.biggestuscities.com/1920