Ahhh, San Sebastian
. There is a restaurant in the suburb of Lasarte
named Restaurante Martín Berasategui
. It was recently ranked as the second best restaurant in the world by TripAdvisor. I had one of the best meals of my life there about ten years ago. Fabulous cuisine. Pricey but worth it.
The route you'll be driving has too many attractive destinations and diversions to count. Carcassonne
France is a must. It is a medeival fortress walled town. I believe it is the largest and best in Europe. Carcassone Video
There are many interesting things to see and do in the Provence
region from Avignon
YouTube has become a treasure trove for travellers. You can type in the name of any tourist locale and see multiple videos ranging from drone flyovers, to walking tours, to professionally done travel videos. Spend some time there and you'll get a great feel for what a place is like and whether you want to go there.
I certainly agree with Jean from France and his recommendations. You can day trip to Biarritz
from San Sebastian.