The good news is if you're in Cascadia now, there's not much point to buckskins. You might get away with them for a mostly-indoor life nowadays, but explorers who tried like Lewis & Clark found that the hides rotted too quickly to be able to tan them fast
enough to keep up with wearing them out. Too wet; even modern commercially-tanned leathers mildew if left alone too long. There's a nice line about Sacagawea's response to the vote about which side of the river to camp on for the winter: "I don't care where there's more elk (wapiti), as long as we're near a good patch of wapato (duck potato)."
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The primary material for garments in the coastal climates was processed from the inner bark of cedar (rot-resistant), often lined with wool; or a cedar warp (loom-strands) would be used with woolen weft (weavers).
Some cultures had intense weaving traditions e.g. look up the Chilkat blankets or "Raven blankets". Here's a mention:
from
http://yaboindhisblanket.blogspot.com/
The
local Northwest Coast natives reportedly had 'wool dogs,' special breeds that were kept separate from camp dogs and bred for their spinning-quality fur/fiber. Spindle whorls are among the cherished heirlooms / archeological artifacts from traditional pre-contact culture.
Hats were also traditional, often cedar-bark or split cedar-root, with other materials for color, or painted with paints made from black tar, or sometimes reds and whites. I assume they may have used the same salmon-egg paint base as for the canoe painting, it
should stick equally well to tightly woven cedar hats.
http://commons.wikimedia.org/wiki/File:Haida_hat_c._1895_03.jpg
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As far as I know (yet), the inland peoples (e.g. east Cascades, Great Basin) made more use of skins and furs, but also used plant fiber materials. Still looking into that one. It's dry enough here for good tanning conditions, and cold enough that I think you'd need either furs or good woolens. Apparently someone related to the locals may have been responsible for the oldest known American clothing, the woven reed sandals found in a cave near a former glacial-meltwater lake in eastern Oregon, dated to something like 8000 BC.
Let me know if you're passionate about learning more of this stuff, I may have some lessons or links stored up somewhere.
-Erica W