Donald Trump Donner Family Documentary

Was it America: The Story of Us on History Channel? He appeared on that series multiple times as a "Real Estate Expert and Businessman" or something to that effect. He was also a celebrity prior to his presidential run, so he was already well-known. They had a lot of celebrity businessmen like him on that series, like Mark Cuban and other real estate guys, in addition to actual historians, authors, even actors, I think. It's a well done series, we actually watched the DVD in high school on days when there wasn't much else to do. They mostly had Trump comment on stuff like urban development in New York, not sure why they'd have him talk about the Donner party. I do seem to remember them covering the issue though, during the westward expansion episodes. Even if it's just one incident, it gets brought up a lot in the media (probably for the shock value).

EDIT: Yes, I'd definitely say this is it. Quite an interesting cast. Donald Trump, Brian Williams, Buzz Aldrin, John Legend, Sheryl Crow, Colin Powell...oh, and Liev Schreiber narrating.