Yeah, I would not view Schweitzer as PNW if you're from this area. The Cascade areas are more PNW where anything west of the Cascades is more INW. However, for a guy traveling from the eastern US, all WA, OR, ID could be viewed as PNW. I think most of us who live here agree with your take.
As a skier coming from far away, I think of PNW ski areas as those close enough to the ocean where coastal weather patterns predominate. Interior BC, Idaho, and Eastern Wash/Oregon are a different climate - more sun, lighter snow - so I put them in a different category. YMMV.
FWIW, here's what the wikipedia editors have come up with:
Definitions of the Pacific Northwest region vary and there is no commonly agreed upon boundary, even among Pacific Northwesterners.
A common conception of the Pacific Northwest includes the U.S. states of Oregon and Washington as well as the Canadian province of British Columbia. This definition is often restricted further to include only the coastal areas west of the crest of the Cascade Mountains and Canadian Coast Mountains.
Broader definitions of the region may include the U.S. state of Alaska, the Canadian territory of Yukon, the northwestern portion of the state of California, and may reach east to the Rocky Mountains.
Definitions based on the historic Oregon Country reach east to the Continental Divide, thus including nearly all of Idaho and parts of western Montana and western Wyoming.
Sometimes the Pacific Northwest is defined as being the Northwestern United States, wholly in the United States. Often these definitions are made by government agencies whose scope is limited to the United States.
Some definitions include, in addition to Washington, Oregon, Idaho and British Columbia, Southeast Alaska, western Montana, the coast of northern California and a small part of northwestern Wyoming.