For most basic jobs they ask you to bring your own black pants, black shoes, and black belt. When you are in an admin or management role they often let you know you can wear business casual. These are my recs for most positions!
Having items that are versatile is key! I highly recommend black thermals or base layers, even in the summer because early and late in the season it can get cold and it is good to wear.
Items to help bear the elements. Most jobs say you need a plain black belt but it is usually optional. You are usually allowed to wear a plain hat or beanie. Sometimes later in the season you are given a jacket or hat to wear with the company logo.
It is important to have a good quality jacket. If you do not come with one- you can go to town on your next day off to get one or at a thrift store.
It is so important to be sure you have great undergarments that are durable, comfortable, and reliable. Once you are there, it could take 3-6 hours to get to town to buy different ones or a month to receive them in the mail.