What kind of things are you interested in? What places will you be going?
There are the monuments and museums. There is the history of the area itself, how it was designed, who designed it.
I would be so excited too. I think I would be reading everything I could get my hands on. I went to Transylvania a few years ago and read all about the area, Count Dracula, the beliefs and stories. When I went on the tour it meant more because I already knew some things and the guide added to that knowledge.