If you are near Seattle, head to the two oval areas...downstream of the mountains of Vancouver Island or the Olympics. Cloud free conditions. Seattle is in a convergence zone and will NOT be a good location to view the transit. The coast will be decent...off and on clouds...but there will be gaps. (I have folks there right now reporting decent viewing) Same with the Willamette Valley. If you are driving south on I5 you will hit the clearing from Tacoma to roughly Olympia.
