I took a look at the review of the film in the New York Times. The reviewer, Matt Zoller Seitz, understands that it's supposed to be a hokey movie, filled with cheese, although he does criticize it even within that genre (he points out that compared to films like the Indiana Jones series and "North By Northwest" it is lacking).
The best part of the review, however, is when Seitz attempts to lay out the plot. He begins with a rather straightforward recounting of what happened with a Gates family ancestor and John Wilkes Booth:
"Booth just happened to shoot Lincoln on the same night that he and a co-conspirator pressured Thomas Gates into translating a diary page that disclosed the location of Cibola, the fabled lost city of gold. To clear the Gates family name, the good guys must prove the existence of Cibola by finding the long-dispersed fragments of a map, one of which is hidden in a compendium of secrets handed down from president to president."
And then we get this little gem:
"To acquire the cleverly named Book of Secrets, Ben plots to kidnap the current president (Bruce Greenwood) and blah, blah, blah purple monkey dishwasher."
I know it's been around for a while, but I think that will become my new catch phrase.