I have a couple of observations from a historical context (yeah, I understand it's a Hollywood production).
The show indicates the wagon train assembles and starts the trip from the sin city of Fort Worth, Texas. I did a simple Google search of railroad maps in 1883, and they show that Fort Worth was a major railroad hub. In fact, the women of the Dutton family arrived in Fort Worth by train.
So, since they were headed to Montana, makes one wonder why they didn't utilize the railroad to get to at least Salt Lake City or Denver. They only had the one wagon so they could have easily freighted their belongings part, if not most, of the way.
I don't think cost is the issue as James Dutton (played by Tim McGraw) doesn't seem to have a cash flow issue as indicated in the first couple of episodes. Whereas, before the war, wagon train would have been THE way for pioneer families to migrate to the west and northwest, by 1883 the railroads were pretty well established and continuing to grow.