The worst part of the route is south of Yachats over Heceta Head. The road is windy and narrow for 15 (?) miles but doable. Watch for bicycles as they will always appear in the worst spot. Don't panic at the tunnel! The low clearance is at the shoulder, just maintain your your lane position and you will be fine.
If you need fuel Fred Meyer Fuel in Newport is the price setter, has a new station with great access and exit. Right side, near McD's. Also Fred's in Florence. Tight but doable with care.
You didn't ask but 101 is a good ride into your home state. You said I-5 was preferred. I would cut over at Reedsport on OR 38 and 138 but there is options.