Can you go with no expectation and not stray into R talk?
I think she wants to share the drive for just the reasons she stated. You're already mindreading about why she's asked you to go so I have my doubts you can do the drive without expectations.
This one decision won't make or break anything because in your W's mind, she's gone, no longer your W, but you do share children so she's attached to you for life in that way.
Me 57/H 58 M36 S 2.5yrs R 12/13
Let me give up the need to know why things happen as they do. I will never know and constant wondering is constant suffering. Caroline Myss