I wear wool and acrylic sweaters as a mid layer. I buy them at thrift stores and wash them. I let them dry overnight in freezing cold temperatures. They are so much better than a cotton hoodie. I don't get some of the fashion trends on the mountain like wearing a long tee-shirt and having it hang out of your jacket. That is gonna soak up the snow into your core. Sweaters are breathable. Wool and acrylic is moisture wicking and water resistant. They are great for warm spring days when worn with out a jacket.
You should buy waterproofing spray for your outerware. After you wash it, some of the finish will come off and make it less water proof. This is when you should treat your outerware. Use powdered detergent and follow the care label.
the OP is giving great advise on how not to freeze. You should follow this even if you are not riding in the backcountry.
IT AINT EAZY BEIN STEEZY