Thanks for the suggestions. Still apprehensive about riding on the west side because afraid of getting buzzed by angry drivers visiting the wineries, otherwise it would be my first choice.
I realize this would be different living there you might know how to deal with it. Would rather ride on roads with some shoulder and little traffic.
The high in Paso Robles is going to be 100 so we would have start early and finish by 1pm. I was also looking at options closer to the coast like Old Creek Rd out of Cayucos but wonder if its too steep on a tandem, looks like 10% for a few miles.