i know there are a few farms on the western slope of CO. (grand junction south to montrose? )
im not sure if their
volunteer opportunities, but i know there are some out there.
oregon and washington, as i understand it, have a decent amount of hop growers as well.
good luck.
http://www.cloud9farms.com/ - Southern Colorado - Zone 5 (-19*f) - 5300ft elevation - 12in rainfall plus irrigation rights
Dairy cows, "hair" sheep, Kune Kune pigs, chickens, guineas and turkeys