RE: Wool clothes and Elk hunting
I like the woolrich techno wool pants. They are not any heavier than a pair of jeans, not overly itchy, and are machine washable. My hunting is usually a combo of hiking and setting still. If I were on stand somewhere all day, I would get heavier wool I think both Cabela's and Codet make a similar pant.
I like heavy wool shirts like the Alaskan Shooting Shirt by woolrich. I usually wear a very light fleece (worsterlorn from Cabelas) shirt and then use the wool shirt over that. If hiking or packing meat, I remove the wool shirt and put it in the pack.
For a backpack hunt, I would bring one extra fleece undershirt shirt, and maybe a some lightweight pants (if you have the weights) in case you score and you want to hike out in comfort.