Apologies if you have seen this before! I just found this article, it is written pre National Treasure 2, but contains some really interesting stuff!
Some of this I have read before, but not all in one place or in such depth. Comments from the producers, director, writers, filmmakers as well as the actors! It is great to hear the passion from everyone involved and interesting to hear more about Turtelbaub's vision, and how he and the writing team approached things.
Enjoy!
http://www.wildaboutmovies.com/movies/National-Treasure-2-Movie.php