Hi Priscilla,
Thank you very much for your inputs/critics. Based on your suggestions, I have revised my itienrary as below:
2 nights in Bayeux - Explore Normandy, DDay beaches, and Tour de France.
Get to MSM in the evening, after spend more than half day to continue exploring Normandy - 1 night in MSM.
Then drive from MSM to San Sebastian. The trip takes 7.5 hours.
4 nights in San Sebastian - Day trip to Bilbao, Guernica, and Pamplona.
1 night in Lourdes (3 hours driving from San Sebastian to Lourdes)
Drive from Lourdes to Nice (7 hours driving), then we will stay in Nice for 3 nights. Return car.
Take the train to Cinque Terra (4 hours). Spend 3 nights in Cinque Terra.
Take the train back to Milan - Stay overnight before the flight home.
I realize that my plan is a lot of driving, but I can compensate for more than 7 hours driving to spend 4 nights in San Sebastian. And same thing with driving from Lourdes to Nice, therefore I will spend 3 nights in Nice.
I cut down the Milan part, just take the train to Milan from Cinque Terra in the afternoon, spend overnight in Milan, before the flight home.
Again, thanks a lot for your suggestions.