The story follows the journey of a family, the Petersens. The "Grand Tour" is supposed to be Douglas' redemption in the eyes of his wife. She is about to leave him and there is nothing he can do about it, but he is determined to make her stay. 
His journey as a father has been a rough one and Nicholls has drawn out a "what to do/what not to do" list for parents. There's a lot of sensible advice which I would gladly take, but everyone's parent-child relationships is different. 
There was a lot of details of art and architecture which I could do away with. I feel like 40-50% of the book was just descriptions of the scenery and the paintings. I had a hard time imagining them and got a little frustrated. 
Overall, it was a bit of a slow read. I have mixed feelings about it, there were some parts I thoroughly loved because I thought the dialogues were brilliant and funny. But some parts, I just wanted to get over with.