African Americans involvement in the westward expansion and the 'old west' in general is something that we hear nothing about. What was it like then for African Americans, particularly in the late 1800s? BTW the book (fiction) is worth a read if you want a really great, not so predictable 'old west' tale.
The West could be a place of opportunity for African Americans. One should never lose sight of the fact that racism was the norm in the nineteenth century, and the West was no exception, but the worst of the racist venom tended to be directed against Chinese immigrants and Native Americans. African Americans were few in the number, and so society could afford to treat them with a little more generosity.
In Virginia City, Nevada, for example, with a population that never exceeded 25,000 and hovered around 15k to 20k, African Americans never numbered significantly above 100. We excavated Virginia City's Boston Saloon, which was an African-American establishment, and when compared with the three other saloons we excavated, we found it had the best crystal and the best cuts of meat. Documents associated with the African American experience shows they attended integrated schools and were generally treated with a certain amount of respect. Keeping in mind that racism was the general rule.
A good source for this is Kelly Dixon's Boomtown Saloons or my book Virginia City: Secrets of a Western Past (2012).