"The Vanderbeekers Make a Wish" by Karina Yan Glaser

This series continues to be a complete delight!  I probably start all my reviews for these books this way, but it's true.  I love this fictional family.
In The Vanderbeekers Make a Wish, the kids are trying to find a way to make their father's upcoming 40th birthday extra special.  They hit on the idea of recreating a road trip he was supposed to take with his own father after graduating from college, but which never happened because their grandfather died.
The only trouble is, their other grandpa...