We'd love to have you!
It does rain a lot, but it is a different kind of raining. Generally it's off-and-on rain. Not a continuous downpour, although we certainly get those too!
http://216.55.5.229/ubb/wink.gif
Our dogs have a covered outdoor kennel area with a doggie door into the shed.
You just have to take shorter walks in between the rain. And keep a throw rug and towel near the door when they come in to wipe muddy paws.
Where in Oregon are you considering moving? Eastern Oregon is a different animal altogether than the Willamette Valley. Eastern Oregon has much more severe weather (very hot to extremely cold) and is more desert. The Willamette Valley is more wet and milder climate (rarely snows; 90 degrees is extremely hot for us).