Trip Bicycling Suggestions for a 67+'r and wife

May 12, we are going to CA with the following Itinerary:

May 12, 13, 14, 15 - Staying at Half Moon Bay, trips to Stanford, Monterrey planned.

May 16, 17 - San Francisco downtown at Westin Hotel - our son and daughter-in-law are receiving a prestigious award on the 17th, which is why we are going to CA in the first place.

North on US Highway 1
May 18, 19 - Gualala (Fort Bragg was entirely booked for two big weddings)

May 20, 21 - Eureka

May 22, 23 - Gold Beach, Oregon

May 24, 25 - travel back to San Jose on I-5

May 26, Return to Denver

We like to bike along the way, and will be renting bikes as appropriate. Due to her recent knee replacement, my wife (69yo) will likely not be able to bicycle more than about 10-12 miles or so at a time, emphasizing level ground. She does NOT ride in road traffic, although a little-traveled country road is ok.

Any suggestions for things to do on the trip or bicycling along the way?