Traveling to Oregon and Washington what are the must do's

Hi all

My wife and I are travelling to the North West between August 25 and September 18th

And I thought I would ask you guys what are and where are the must do’s. Very keen to get some good photographs on this trip

The plan is to fly into Seattle drive up and spend 3 day in the San Juan Islands (Friday Harbour), then across to lake Chelan, Wenachee and Leavenworth for 4 days. Then head down to John Day Fossil beds and bend area for 3 days. Then further down to Creator lake for 3 days, then across to the cost to Otter Rock and Cove for 2 days, back up the coast to Seaside Cannon Beach then finally back up to Seattle for the last 3 days. Now I know you guys are very keen on this area, specially David Nall so I was wanting some input and the best spots. Please all suggestions are welcome.
Paul (by the way were from Sydney Australia)