Hood canal is definitely going to be the most diver friendly in the area. We make the 4+ hour drive from Eugene a few times a year. One site on the coast that I've actually had some pretty decent dives is the Newport Fingers. Like most coastal sites they are tide dependent and subject to low visibility when there is a strong onshore flow, or lots of silt in the rivers, or they decide to dredge the channel etc. Entry is over over some jetty boulders, but you can drift from one finger to the next depending on the tide, or stay on the side protected from the current. I don't think it's 40ft deep at high tide if you shove your head in the sand.
My favorite Oregon coast diving is down in Port Orford (more sheltered, not as tide dependent, but still not simple entry) but that's a long haul from Portland, and you could be up in the straits instead.
My favorite Oregon coast diving is down in Port Orford (more sheltered, not as tide dependent, but still not simple entry) but that's a long haul from Portland, and you could be up in the straits instead.