Highly recommend you travel the coast. All of it. And also inland, especially Crater Lake and along the North Umpqua River. Here's more info...
http://vickiandsteve.com
then 2010 postcards from July 8 through Sep 14. That covers our month on the Oregon Coast plus the North Umpqua. We were there earlier in the year than those dates suggest. As for Crater Lake, those postcards are yet to be published but it's absolutely worth a trip to see.
Also, the Columbia River Gorge area going east from Portland. Get off the interstate and drive the highway through the gorge area. Don't miss Multnomah Falls (and the other falls) and also Herman the Sturgeon and the fish ladder at the Bonneville Dam.
Near Portland is the site of the end of the Oregon Trail, along with a museum.
And there is so much more. Oregon is such a beautiful state. We need to go back a few more times.
Have a good time. That's a terrific place to go.