What clothing did they wear during the Westward expansion?
Synthetics had not been discovered and these folks were not Frontiersmen. They didn’t have the skills to obtain and treat hides for clothing while they traveled, and even if they had the techniques for assembling garments from animal skins was quite different from those used with cloth. In addition, their time was well occupied with travel. When they reached their destinations itinerant pack traders supplied their needs until a store was established.