What were some of the real reasons that Sal's grandparents were going to Lewiston, Idaho?

Walk Two Moons is a novel that has many different stories woven together to build the plot. Creech, the author of Walk Two Moons, cleverly reveals only small pieces of the characters' intentions throughout the book so that the story has time to unfold. Many details in the text are not as they appear; so is the case with Sal's grandparents and their trip to Lewiston, Idaho. When the grandparents first approach Sal about taking the trip with them, they tell her that they would like her to come along so that they can spend time together and see the whole country. However, Sal is not convinced that these are their real reasons for going, and she very clearly lays out the motives of her grandparents in Chapter 2 when she states:

The real reasons were buried beneath piles and piles of unsaid things.

Some of the real reasons include:
1. Gram and Gramps wanted to see Momma who was resting peacefully in Lewiston, Idaho.
2. Gram and Gramps knew that Sal wanted to see Momma, but that she was afraid to.
The tragic event that leads the family to Idaho is one that they struggle to talk about, which is why Gram and Gramps are not clear about their intentions. Even with their veiled motives, Sal can see that the real reasons that Gram and Gramps travel to Lewiston, Idaho are to find closure for themselves, and to provide support for Sal as she struggles to find the closure she needs as well.