Summer Madness by Janet Lambert (1962)
While Ginger is working out the details of her campaign, her parents have also been struggling over a decision about the future that will change Ginger's plans, not only for the summer, but for a long time to come. Mr. Johnston is going to take a job in another city, and the family will have to move there.
This is the situation in which Ginger finds herself. Pulled between her loyalty and love for her parents and her devotion to Spark Plug, the emotional adjustment she is asked to make proves to be the biggest she has yet had to face. What is Ginger to do about Spark Plug, about her friends, about her whole way of life if her parents move away from Cheltham.
Janet Lambert, as always, writes with a sharp insight into the continually changing world of teen-agers and with a sympathetic understanding of the problems that young people must work out for themselves. (from the inside flap)