The Oregon Trail was a passage used by early settlers to start a new life in the north western United States. Of course it wasn’t just an easily followed road, people made their way out there by any path possible, that is to say there wasn’t a set trail to follow, even though it was called the Oregon Trail.
Probably the most useful supply were the wagons the settlers used, and the mules used to pull them. The settlers didn’t want to over burden the mules and the wagons themselves so they were not able to bring whatever they wanted, they had to be frugal. Of course they still brought what they could including: bibles, school books, clocks, mirrors, furniture, many of the things that we take for granted in our homes. Many of these items had to be abandoned along the way.
The supplies of most importance were the ones brought along for survival purposes, ropes, chains, extra axels, and an assortment of other items to repair broken down wagons, or help the wagons along in difficult terrain were of the utmost importance. Other tools and guns for protection and hunting were also important, as well as cooking materials were also important. Of course we shouldn’t forget food itself and warm clothing; it wasn’t a summer vacation for the settlers.
This link will provide you some more information.
http://www.endoftheoregontrail.org/road2oregon/sa15outfitting.html