On the Road with Mallory — Laurie B. Friedman

Mallory has a new journal, just in time for her family's vacation to the Grand Canyon. She can't wait for the road trip -- until it turns out that her cousin, Kate, is coming along. Kate would rather read a list of "fun facts" than have actual fun at the amazing stops along the route. And when Kate catches Max texting a mysterious girl, the backseat of the minivan starts to seem like the last place Mallory wants to be. With everyone arguing and keeping secrets, can Mallory somehow save the trip?