I think “r” stands for renter but it might stand for rear.
There are too many ‘r’ entries throughout the directory to stand for rear, I think.
I’ve done genealogy for years. The “h” stands for head of household and the “r” is resident. Stanley being the head of the house and Madelyn, the wife, is residing in his house. You have to remember the times back then.
Whether they actually lived there, I don’t know as I wasn’t there. However, I doubt very much the bouncing bundle ever spent a day there.