Walk Two Moons, a road trip and three-layered story.

In "Walk Two Moons" tells about Sal's cross=cointry road trip with  Gram and Gramps, allowing Sal to follow where her mother had traveled before.
Walk Two Moons, by Sharon Creech

Gram and Gramps take Sal on a road trip from Kentucky to Idaho, Sal passes the time by telling them how she and Phoebe attempt to identify a lunatic and a murderer, and behind both tales is the third layer, Sal’s facing and accepting her own loss.

Sal’s other grandparents appear only in one description:

Once I asked my mother why Grandmother and Grandfather Pickford never laughed. My mother said, “They’re just so busy being respectable. It takes a lot of concentration to be that respectable.”

Walk Two Moons, p.15

No wonder Gram and Gramps,–unconventional, impulsively responsive, and in love for a lifetime–so effectively bind the layers of the book. The “respectable” characters are important only in their unimportance.

Sharon Creech mixes tears and laughter in a road trip through sadness, guilt, acceptance, and caring. I’ll get this book of hers back to the library and check out another.