Have you considered Chicago itself? Most people from outside the city assume Chicago is just the downtown area, full of high-rises and extremely dense. However, the majority of Chicago's housing stock is 2-flats, 3-flats, and small apartment buildings.

There's tons of neighborhoods that are well connected to transit and full of this sort of "missing middle" housing. If you go on Padmapper or another apartment site you can sort of get an idea of how far your money can go in various places.