Breaking News, Nancy: Highway 1 (Pacific Coast Highway) just re-opened this past week, ahead of schedule, after a year-long closure due to a major landslide. Since people were not planning on the coastal route during the time you will be traveling, lodging was not reserved and should be available. There are limited lodging establishments between Carmel and Cambria, but they do span the entire range from very fancy to fancy to moderate to funky to campgrounds. Also various restaurants and endless viewpoints. For beauty and safety, keep your driving to daylight hours, except maybe for dinner, if you are staying along the way.
Other random thoughts:
Seattle: I was there in January and just loved the Chihuly Glass Center, almost unique, although I understand his other museum is in Florida, so that might impact your choice. The Olympic National Park is wonderful, the greenest place I have ever been, and that includes Bali and Kuaui, and the coastal area beyond the Park is wild and scenic too, look into Kalaloch Lodge to stay and for a meal or two, great restaurant there.
Oregon: I agree that the Oregon Coast is very beautiful and very diverse in terms of landscape, seascape and eating and shopping possibilities. I only drove it once, years ago, but found myself stopping every 15 or 20 minutes for varying reasons.
Northern California Redwoods, certainly. Spectacular and shouldn’t take much of your driving time.
I won’t get into the Bay Area and other areas nearby, including Napa, Sonoma, Muir Woods, Lake Tahoe and Yosemite, all wonderful and each different. Keep track of the location of all these wildfires though, they could impact some areas and routes.
Monterey Peninsula, great place where I live. Monterey Bay Aquarium is very special, but entry has also gotten quite expensive. Some hotels or inns may have guest passes, certainly inquire. Be aware that Aug 17 to 26 is “Car Week” here, with a series of classic car events culminating with the Concours d’Elegance at Pebble Beach on Aug 26. Great if you love classic cars, up to million dollar cars, but lodging will be extra expensive and mostly full up, and traffic can be paralyzed during that period.
San Simeon, south of Big Sur near Cambria: Hearst Castle is a unique, over-the-top experience, and I recommend a visit, even if Art Deco castles are not your thing. Hearst Castle is incredible, with a choice of at least 3 tour experiences. Cambria is a nice place to spend a night, lots of hotels and restaurants along the coast there.
Santa Barbara is very nice too, and i’ll leave further south for others (or, you might want to end your trip around here, and leave LA-San Diego areas for later in life!