If you contact many of the rawhide/reata braiders I bet you get at least a few responses. Most of those guys are passionate about history.
Saddle makers are the same way. Both have forums on the internet and I was surprised at how many use them.
There are some good books made from the journals that people on cattle drives kept. If you can't find any in your area's library (I see you're in WA) try contacting some in cattle country. We're interested in how it was done all over the country. There are also many books that have excerpts from missionary priests from that time period and your area of interest. Again, a reference librarian with the tenacity of a terrier will be your friend.
Good luck. I'd love to watch what you come up with (if it isn't smutty!).