Back when we first bought the house, Brianna told me that maybe she would like a hanging tennis ball that would tell her exactly how far to pull into the garage.
I hadn't heard anything more about that idea, until it cropped up again this weekend for some reason.
So, now Brianna has a tennis ball for extra parking precision.
I didn't estimate where the ceiling eyebolt should go as well as I hoped, but this should be sufficient. The string is anchored next to the door to the house, for easy adjustment later.