I've driven that route half a dozen times. Be wary on weekends north of San Francisco, lodging is stupid expensive and there ain't no chain motels, just private inns. The farther north you can get the first night, the better off. Fort Bragg or north and your home free.
The side road from Humboldt to Cape Mendocino is nothing but one curve connected to the next curve. I was awfully busy in my truck, but that sure is a speedster road. Probably nothing over 50 MPH but lock to lock for 50 miles.
At Gold Beach, the jet boat run up river is a unique experience. We went to the lodge at the far end overnight. Nothing like going up a six foot waterfall at 30 MPH and dodging garage size rocks less than a foot away, all in two or three feet of water - literally.
Port Orford is scenic, if memory serves, that is where they launch the fish boats off the top of a huge rock via sling and crane. Just standard procedure. The restaurant in the marina there has great fish.
Bandon, visit "old town" and follow the signs to the Jetty a mile away.
Coos Bay, if time allows, take Mclain -Libby road to Charleston and out to Cape Arago.
15 miles north of North Bend, right turn into Lakeside and Tenmile Lake. That's where I spend my summers - two weeks behind you - otherwise I'd offer a lake cruise and free overnight. North Lake Resort has good campling and is almost across the lake from my cabin. There's also a county campground within walking distance of town. Follow North Lake Road to the end of pavement for a fun drive of five miles.
Winchester Bay (Salmon Harber). Visit Griff's for best fish on the coast. Follow the paved road out into the dune buggy area. Only a few miles. Totally unique view of more sand than you have ever seen in you life, and dunes 100s of feet high. A side road up to the light house offers a beautiful ocean overlook and view of a commercial oyster farm.
Reedsport to Florence - very scenic, keep an eye out for lakes all around you. Catch a few "dunes overlooks" for more sand and ocean.
Yes, the sea Lion caves are unique - and stinky.
Damn, now I'm itching to get going myself. Enjoy!