The cruel irony of the name of this park juxtaposed with your use of the Lakota word that can be translated as buffalo, adds an interesting dimension to your story. It sent me off to do some research.
I like Dancing With Wolves too, even though I see so much more in it than you cited in your description. Often movies, books, and stories concentrate on one side of a story. I loved how it delved into the side most often missed.