Having just purchased a home in the general area of Big Hole, I found myself becoming interested with this piece of American history. I've seen the documentary at the Big Hole State Park, read some of the different publications and as of now, I've seen this movie.
Obviously the "Hollywood" production falls flat compared to facts and figures. However, I did find that this movie makes it's best effort to depict actual events and timing. I also think that considering the times (1975) that this effort is well worth watching. I'm no 70's movie buff but the effects and dialogue more than met my expectations. I think at the very least, this movie would hopefully motivate others to research the specific plight of this group of native Americans.
At minimum, the Nez Perce fought 10+ battles while being chased by about 10 U.S. divisions and all this with only around 100 warriors. They traveled 1300+ miles in about 108 days (over 12 miles per day) before chief Joseph's famous speech. This also marked the last of the big battles between the U.S. government and the Indian tribes.