This is a realllllly charming tale that will drive you sane!
From back cover:
When 12 yro Dana begins to strip away the wallpaper in her new room , she finds that there is a hidden room-containing a skeleton key. With the help of a diary found in the room she learns that her house was once a staion for the Underground Railroad.
Dana, 12, is helping her parents to restore an old house in Kansas as a bed-and-breakfast when she discovers a boarded-up room containing a human skeleton. With it, she finds the diary of Millicent Weaver, a Quaker and early resident of the house. She learns that the house was a stop on the Underground Railroad, and that runaway slaves were taken there by a former slave, Lizbet Charles. Of course, Miz Lizbet is Dana's skeleton, and the cause of her death at the age of 25 is finally revealed at the end of the novel. The story is told in alternating chapters, shifting between the present and 1856, when the events involving the long-dead young woman took place. The best developed character is young James Weaver, who struggles with his family's philosophy of nonviolence and with the secrets he must keep.
skillfully rendered book that will appeal to a wide audience