You have 2 choices as i see it.
1. Go, it's fake and you have had a day (or 2) out and seen a bit of the country and a story to tell your mates how you fell for a practical joke.
2. Dont go and it's real and you missed out on the opportuinity to meet Dan Brown and get a signed copy of the book.
Bit of a no brainer if you ask me. But then again it's not me
