This sounds like "Little Mommy" written and illustrated by Sharon Kane, copyright 1967. The vintage copies from the 1960's and '70's are pretty high-priced, but it has just recently come back into print! I bought several copies at a Winco supermarket to give to my granddaughters and nieces. You should be able to find or order a new copy--happy hunting!
I am looking for a book about a boy and a girl who played house together. The little boy goes "to work" in a little play car (I think a shiny red convertable) while the little girl stays home to look after their baby doll. The book is at least about 30 years old. I am pretty certain it is a Little Golden Book. Does this sound familiar to anyone??? Thanks!