about cotton, wool and fleece
I wear a lot of cotton in moderate weather (early archery deer and spring gobbler) chamois, flannel, and so on, but cotton is near worthless as serious cold/wet weather apparel. There was a nickname for cotton in the SAR world.....death cloth.
The toss up is between wool and fleece. Both are very good insulators, wool has an edge in warmth once wet. Fleece's edge over wool is that it dries out very quickly and will regain full insulating capability much quicker. Wool stays wet longer, and it can get very heavy depending on the thickness of the garment, but it will still insulate fairly well, which is why it remains a staple. Neither fleece nor wool, unlined or backed, will do well in the wind w/o some type of wind breaking shell garment .
I have two pairs of Korean War era OD wool trousers, that are actually big enough to fit me (not to many 260 lb privates), when you can find them they run to small sizes. I've worn them alot over twenty years, and they show little wear. You couldn't buy them from me. With some type of poly layer under them, sometimes two, they do fine in our climate. I also picked up an unlined camo wool jacket, Columbia mfg maybe, and I am quite tickled with it as well.
While I'm at it, an old GI split tail parka shell works very well over fleece or wool as a windbreak, and sprayed with some type of aerosol treatment, well shed water a bit too.