Itinerary help Madrid/Andalucía - where to spend an extra day?

Can you shift that night to Ronda or is everything prior locked in?
It's a tough question because of the train lines! It would be great if you could just hop off somewhere en route back to Madrid, but I don't think that's possible. And a one-night jaunt could be somewhat time consuming, so I would have added the night somewhere else if possible--most would say three nights is minimum for Sevilla.

Hi - the only thing that's really locked in is Madrid and then Sevilla. We haven't booked anything yet for the nights after Sevilla, so we could move Ronda! I think the thought process behind Ronda between Cordoba and Granada is that the train goes from Cordoba to Ronda, and then there's a route from Ronda to Granada with a change at Antequera.

Two nights in Ronda would be great because you can easily see the town on the arrival day and departure morning, and on your full day you could do a long hike or rent a car and explore the area.
Hike doable with public transport: https://www.andalucia.com/rural/walking/railway.htm (can see some caves too)
I have not been to Antequera, but if the train stops there anyway, that is another option for a one-night stay. I always wanted to go to see the rock formations at Torcal (and orchids!), but look into transport to the park.
https://www.andalucia.com/antequera/home.htm
https://www.andalucia.com/antequera/torcal/home.htm

I would want to spend the last night in Madrid, before a transatlantic flight home.

Yes Carlos, you're right, that is the plan - I will try to update the original post if I can.

Thanks for the clarification, in that case I'd put Cordoba at the end, since it's on the way to Madrid and add 1 night to Ronda, you'd need two nights there if you want to explore the nearby Pueblos Blancos, which is best done by car actually, the rest of the traveling can be done with the AVE high speed train.
So my recommendation would be:

Fly in
Madrid (5 nights)
Ave to
Sevilla (3 nights) - rent car
Drive to
Ronda (2 nights) - explore Pueblos Blancos
Drive to
Granada (3 nights) - drop off car
Ave to
Cordoba (2 nights)
Ave to
Madrid (1 night)
Fly out

Hope this helps!

Thanks Carlos, that routing does make sense if we decide to rent a car for more than a day or so.

Valadelphia, thanks for the link to the hike! That looks very interesting, especially if one can take the train back from Jimera de Líbar!

Is it too late to add a 4th night to Seville? Seville is beautiful with lots of important historical and cultural sites. And it’s wonderful for wandering and exploring with its narrow lanes, plazas, fountains, and beautiful architecture. Take a carriage ride. See a flamenco show. I personally think 4 nights is the minimum for Seville.

Or spend one night in Toledo, just before your last night in Madrid. Or spend the last 2 nights in Toledo, depending on what time your flight home leaves the next day. It’s a 30-minute train ride from Toledo to Atocha. Or perhaps you could hire a private driver with van to take you directly to the airport from Toledo.

I suggest spending a night or two in Toledo because there is a lot to see there and it’s so much nicer at night when the day trippers have left and the city is illuminated. If we had seen Toledo as a day trip, I think my opinion would be ho-hum about the city.

I like kmkwoo's idea of spending the extra night in Toledo. There's enough to see there for an overnight, and doing that will free up a Madrid day earlier in your trip. That would mean taking the train into Atocha Station in Madrid, then another train back toward the south to Toledo. It's not efficient but it's the only way that makes sense, and the Madrid-Toledo train takes little time.

Carlos' idea to explore the Pueblos Blancos between Seville and Ronda is a good one if you're willing to drive instead of take the train. Or you could do that as a day trip from Ronda, that being your extra day.