If you are really interested, I recommend "A beast the color of winter" by Douglas Chadwick. Great book on goats.
And like Okanogan says, windy ridges that remain snow-free are pretty important to goats. These can be at pretty high elevation! Sedges, grasses, low shrubs, and tree lichens ("witch's hair") are all important.
That said, keeping low elevation winter habitat more open (ie, not in dense forest) can benefit goats. This is especially important in the dry interior forests that have missed several fire cycles and become more dense. Goats tend to avoid dense forests.