My husband and I LOVED "National Treasure"!! It's one of our all time favorites. We bought the DVD and watch it every time it comes on the movie channels. We love it precisely because it treats the plot so lightly and it does give some very REAL glimpses of history. To see the inside of Independence Hall, Library of Congress, etc., is just TOOOO COOL.....
You mentioned that you and your husband love the film "National Treasure"---it's very popular in our family, too! Last summer my wife and I and the kids took a trip to Philadelphia and walked the "National Treasure Tour". We saw many of the locations they used for the movie, including some small, obscure places. Remember when the female lead hides behind the deli counter? We found that exact spot. The people there were even able to give us little tidbits of inside information! After we left Philly we headed up to Washington D.C. and continued the tour.
By the way, before we started the "National Treasure Tour" we stopped outside Philadelphia and saw the field where "The Village" was filmed. I contacted the owner and he let us take a look around. Nothing is there now, just a big empty field, but it was neat to see it. And yes, we all wore red!