I grew up in the City of Atlanta, in a little area that was extremely friendly and SAFE....in the summer we wouldn't even close the front door, just latch the screen ! For kindergarten I had to walk several blocks to go to a building on the local Baptist church grounds.....they loaned the bldg to the city school system because they didnt have room in the regular school house for us; then 1st and 2nd grades I walked about two blocks away on my same street, to attend school in the Salvation Army church classrooms, because the "big" school still didn't have room for us !
I always wanted to ride a school bus, but in the city if you lived within a 1 mile radius you weren't eligible to ride the bus.....oh, all I ever wanted to do was ride the school bus ! I never did !
I guess the classes were about average size and I know that we had more than one class for each grade...just don't remember