Oooh -- very jealous. Related thread (maybe time to bump?):
http://forum.calgarypuck.com/showthread.php?t=105946
I've heard great things about the Oregon Coast; this thread confirms it. If it was me, I would spend as much time on the road and away from SF as possible -- do Highway 1/Big Sur, do the Oregon coast, and visit as many places as you can along the way (especially in WA/OR/CA). Flights are easy to get to SF so if you want to go back you can. Similarly, it's not that far (relatively speaking) to drive down to Wyoming/Yellowstone, so if you want to skip that and do it another time, it's possible. However, driving all the way out to the coast isn't something you can do very often/easily (unless you have a lot of vacation time on your hands), so I would take advantage of that opportunity and maximize whatever time you have out there.
As for shopping -- OR and MT have no sales tax; AB residents are exempt from WA sales tax if you show your driver's license as proof you're from Alberta