Final itinerary, please review

Comments.............
On arrival immediately adjust your tummy clock to the Spanish culture by eating your dinner after 8 pm. Doing so will open your trip to participating in evening activities which many tourist miss by sticking to their USA based tummy clocks. Where you are staying an adjacent plaza filled with benches, watch how this area comes alive in the evening. Take a long walk, enjoy some tapas (but leave room for dinner) and get to know the street scape in your new neighborhood.
Be sure and obtain your IDP from AAA prior to leaving the USA.
Do you have a specific purpose for driving? Bus service in Spain is excellent and leaving the stress of driving to a professional allows more time to enjoy the scenery. We have rented cars when a specific destination was not easily accessed via public transport and while the task is not daunting, it does add an element needing to be "managed". We have made an effort to adjust our schedules to take advantage of public transport and been richly rewarded with experiences not found in any tourist guide.
We use buses and trains while traveling in Andalusia and absolutely do not recommend driving to Madrid.

I’m a rental car person, but if you’re going directly from city to city, then public transportation may be best, based on your itinerary. You don’t need a car in the cities and it will cost €15 to €20 per night for parking. If you’re stopping in some small towns en route, then by all means, rent a car. The Parador in Ronda is in a great location and provides a great view.

UPDATED Itinerary

October 4, 2018 Arrive Barcelona 6pm - Airport to hotel? (After traveling all day and night I'm thinking taxi or uber.) Staying at Cool Rooms-Paseo de Gracia
Oct 5 - Barcelona City Tour
Oct 6 - Park Guell and Montjuic Castle
Oct 7 - Montserrat Winery Tour
Oct 8 - Fly to San Sebastian - Arrive 5:50pm - Hotel Maria Cristina - How do we get from airport to hotel?

The best way to get from San Sebastian Airport (EAS) to Maria Cristina, a Luxury Collection Hotel, San Sebastian, San Sebastián without a car is by train which takes 30 minutes. There is a direct train from airport departing from Irún and arriving at Gros. Services depart every 30 minutes, and operate every day then 7 minutes walk to hotel.

Oct 9 - San Sebastian (Rent Car at San Sebastian)
Oct 10 " "
Oct 11 - Day Trip to Bilbao *******(No Need to check in another hotel in Bilbao, San Sebastian to Bilbao is not that far so stay at same hotel in San Sebastian)*******
Oct 12 Bilboa - Day Trip Guggenheim Museum
Oct 13 Fly to Seville - Arrive 2:50pm - 4 nights at Hotel Posada del Lucero
Will follow suggested activities in Rick Steve's book - Anything not to miss?
QUESTION: Do we rent a car in Seville and drive to Ronda, Granada and then Madrid? Or use trains? Yes Rent a Car in Seville to drive to the towns of Andalucia for conveniency***.* Ronda and Sevilla are not that far apart so stay in Seville for an additional night and do a day trip to Ronda and if you have time tour Arcos De la Frontera.******
Oct 16 - Ronda - Day Trip
Oct 17 - Granada -Hotel Santa Isabel la Real
Oct 18 - Granada
Oct 19 - Madrid - Hotel Artiem
Oct 20 - Day trip Toledo or Segovia (Go to Toledo)
Oct 21 - Tour El Escorial - (Day Trip from Madrid)
Oct 22 - Valley of The Fallen (Day Trip from Madrid) http://www.feelmadrid.com/valleyofthefallen.html
Oct 23 - Depart Madrid - flight at 10am - so early to the airport
Thanks you for the review and suggestions.

I would suggest a rental but you really need a 2nd night at Ronda to allow you time for exploring white villages. Also, I don’t see any time for Córdoba.