If I were you, here would be my proposed route:
Head west into Columbia River Gorge and see what you need there. Then direct west into Astoria area. From there, south along hwy 101 to as far south as you want to go into southern Oregon. Then head to Crater Lake area followed by Bend. And this is that part I can't believe all these Oregonians didn't mention, make plans to stop in John Day and the must see John Day Fossil Beds National Park - Painted Hills Unit. It is a treasure that most either don't know about or neglect to mention. From there, you can travel up hwy 395 through Pendleton to head home.