This is a tough question, because the roads west-east in this area are either super rural with few services, or major roads with high traffic volume, especially in the summer. I'm originally from northern California. I would not want to ride from Crescent City to Grants Pass, but mostly due to the section from Crescent City to Collier Tunnel. LOTS of RV traffic and big trucks, with very little to negative shoulder on curvy roads wrapping around giant trees. But if your tolerance for traffic is high, it is gorgeous. 96 is beautiful, VERY rural, so you'd want to check services and plan accordingly. Does the route you are taking go from O'Brien to Happy Camp on Grayback Rd? Or where do you drop onto 96? If it is to Happy Camp, that section is beyond rural, so plan accordingly. You won't run into much traffic. Lots of no cell service areas out there.
We are doing a loop this summer, combining Sierra Cascade and Pacific Coast, too, July and August. Bend, OR north to Sedro-Woolley, then South on Pacific Coast to SF, then east to Truckee and back North on the Sierra Cascades. So maybe we'll cross paths!
-Emily
P.S., If you are flexible in direction, I recommend doing the coast section from north to south, due to prevailing winds on the coast. So north on Sierra Cascades and south on Pacific Coast.....