For the past 6 years I have used Duluth Trading Dry on the Fly fleece lined nylon cargo pants. They are at least the equal in features and (IMHO) in quality to RailRiders fleece lined nylon pants but definitely for less money.
These D.T. fleece lined pants are virtually windproof and really DO “dry on the fly”. Worn over a heavy weight base layer they have been good for me down to 10 F. while just walking and wearing gaiters.
For sub zero F. weather I have Thinsulate lined Gore-Tex ski pants that are great to -20 F. and lower with proper base layer. They actually kept me warm once at -40 F. I never want to see temps that cold again.