My son devoured the book in a few hours and I followed soon after. I admit that I enjoy reading children's books. They are fun and full of adventure and makes me feel like a kid again.
I enjoyed this one. It reminds me of my own road trip not too long ago. Albeit this one is a little exaggerated where even a pig came along for the ride. I can identify with how mum tries to make plans for the family based on magazine recommendations which don't always turn out exactly as shown in the glossy pages of a magazine. I am not going to give away any more spoilers here. You'll just have to get the book to read for yourself.
I find the Wimpy Kid series suitable for boys and girls aged around 9-12 and not so much for younger children.
My girl didn't really enjoy this Book 9 though. When asked her why, she said there were too many negative things happening one after another on the trip right till the end of the trip. Perhaps boys may enjoy this sort of humour more.
It is light reading if you don't try to break it down and make too much of it. No great humanity lessons here. Just enjoy the humour and the adventure.
Finally, among all the teaser trailers for the book, I like the following one best where author Jeff Kinney shows us how he illustrates the characters in the book.