Look at the mountain hardwear chugach pants.
Or if you want camo, Sitka gear makes a pair, the Kelvin pants.
They are light weight, pack down small, but provide a lot of warmth.
They also zip all the way up the leg, so they are easy on, or off...
I take these on most all hunts here. Nice to zip on when glassing, or to add warmth at camp. Also allows to take a lighter sleeping bag.
