I am interested in Antequera. Chani, what would the drive be like from Rondo to Antequera? We will be renting a car in Seville and dropping it off in Granada. The roads are in good condition and well-signed. The roads through the hill towns are scenic and well-graded. Just a note, the speed limits for curves were just about the maximum I felt comfortable taking them at . . . unlike in the U.S., for instance, where you can usually take curves at much higher speeds that posted. You go right past Antequera on the main road between Ronda and Granada. Antequera is on a hill surrounded by plains. If you want to see the town, you should stay up on the hill, in the old center. There are hotels near the highway, more convenient if you just want a place to sleep. You could probably leave Ronda early, visit the pink lagoon and hike in El Torcal and still get to Granada for the night.
You also mentioned going straight to Cordoba when we arrive in Madrid. Should we spend the night there or head to Seville after touring Cordoba? I'd recommend an overnight there because  it's your first day, you may not have a lot of energy and  I really liked it in the evenings.
You also mentioned that the ticket to Cordoba would include transport to the Atocha station. Can you explain how we get to the Atocha station from the airport? There are Renfe (the Spanish rail system) trains that connect the Madrid airport to Atocha. The train station is in the airport. Just look for signs for trains or Renfe. There's a ticket office where you can buy your tickets. There are several very dedicated volunteers on the Spain Forum of Trip Advisor who have written excellent, detailed guides for using trains and for driving in Spain. Go to any of the Spain forums there and look at the "Top Questions" section on the right. They will help you immensely. You can save a lot of money on train tickets by buying them online when they go on sale. It used to be 62 days in advance but I found lately that it could also be 3-4 months in advance.
Does it sound reasonable to drive from Seville to Rondo with stops in Jerez and Arcos or Grazalema? Do you mean in one day? I guess you could stop for a few hours in Jerez, then in Arcos and still get to Ronda before dark. . . a bit rushed, perhaps. You could also drive to back to Grazalema and visit other hill towns too as a day trip from Ronda. While you're looking at the TA Top Questions, also read the one about driving in Spain. By the way, every driver must have an interational driving permit.