Published before 1989, likely current setting is late 70's or early 80's. Teenage girl with mom and brother, no dad, move to a 3 story house off the California coast line. The house has a curved driveway with a tree stump in the grass. The family does not have a car, but the girl keeps hearing a car idling in the driveway. Then starts to see an oil leak when everyone else sees dirt. Later she sees a 50's style car (blue if I remember correctly) and a man in his late teens or early 20's in a bomber jacket. Man died in a chicken race when his car went over the cliff. He is asking the girl to help him find his girlfriend from that time, who used to live in the house. Detail about the house is that the circular window on the 3rd floor always breaks out even after the tree was cut. Which used to be tall enough to reach the 3rd floor window. Below the house is a small cottage surrounded by lots of flowers and the person who lives there befriends the girl. She is the new girl in school and everyone thinks she is crazy, especially when the ghost of the man in the bomber jacket starts to dance with her on the school's cruise along the coast. Of course, no one can see him and everyone thinks she is dancing by herself. The cover has the picture of the girl, brunette I think, standing in the driveway, with a see-through image of the man in the bomber jacket and his car behind her.