The Girls Trip by Ally Condie

From the author of Reese's Book Club Pick and instant USA Today bestseller The Unwedding, a novel of suspense and friendship about three friends who decide to disappear from their lives for a few days while on a trip to a national park—only to have one of them vanish.
 
Hope, Ash, and Caro met at an online book club. Over the past two years, they’ve been there for each other in every way—except in person. When each of their lives reach a crossroads, they decide to meet in real life at the gorgeous Sonnet Resort at Eden National Park.
 
Hope, an actress, has become entirely too famous and needs to get away from it all. Ash, a successful online entrepreneur, isn’t sure what has happened to her marriage. Caro, a doctor, has lost a patient and doesn’t know if she wants to carry on or start all over.

And none of them are telling each other the full story…