Here is a link to a new feature length documentary about the making of the film Gettysburg. The documentary includes interviews with historical advisors and reenactors who worked on the film.
Cool! Gonna check it out. I have enjoyed several videos on Youtube lately relative to the anniversary of the movie. One of my favorite so far is this one with Patrick Gorman (Gen. Hood) revisiting the barn in which he cried out in agony, "You Should have let me go round to the right!"