Wow, you weren't kidding about the relative density between those areas. I'd consider Oak Park dense compared to most suburbs, just not as dense as some neighborhoods in Chicago. I'm most familiar with the north side neighborhoods and had those kind of lots in mind, with their near non-existent front yards, with front steps right off the sidewalk, and virtually no front driveways.
Apartment building on Pine Grove in Lakeview for me and then a beautiful old two flat in Ravenswood. My rent in Pine Grove in 1999 was $400 I think for a two room apartment.
https://www.google.com/maps/@41.9405345,-87.6750174,3a,75y,2...