Time is where the problems are, you really don't have enough of it for the journey's you have planned. From SF to Eugene by the most direct route on I5 would take 9-10 hours with basic stops, to drive via 101 could take anything from 12 to 14 hours without time to stop at the Redwoods or much else other than a quick photo opportunity from a viewpoint. If you wanted to take the coast north of SF on CA1 it would take even longer and either option is far too much for a days travel. [2 days 101 or 3 days on Ca1/101] You can make the trip work but scenic detours and coast roads add time that you don't have unless you add those days or cut back a little.

Mt St Helens is great, but even that detour would add 4 hours to enjoy the place. Mt Rainier is a spectacular place and while in Portland the Historic Columbia River Gorge is a wonderful drive and if you exited Portland heading east through it you could then head south on US97 to Crater Lake, but again you need to have the time or cut back on other places. Is Vancouver a must for example ?