This was a group of shorter chapter books about a young girl (maybe 12 or 13?) who goes to live with her Grandpa. He’s the classic crotchety but with a heart of gold character. She’s a typical growing-up girl, trying new things, dealing with friendships, etc.
The characters live in a small, quintessential American town. If I were guessing, I’d say they’re set in the 50s. I read them in the late 70s and they seemed “old-fashioned” to me then — but there was electricity, cars, etc.
I recall maybe 3 or 4 books in the series. I’m sure one was set at Christmas. Another was about her entering a Bake-Off.
I think she had a very ordinary name, and this may have been in the title — Margaret, or Elizabeth?
I also sort of think they were published by Scholastic, and I also think that the Christmas book was made into a made-for-TV movie, that perhaps aired in the early 80s?