Travel in the Andalucia region of Spain

Seville is the sort of the midpoint. Seville to Cordova is about an hour and a half. Seville to Granada, more than two. Seville needs more time than the other two,. You might could do Cordova and Granada is one day each, but not very well, especially considering the time getting back and forth. I'd move around.

you could do cordoba as a half day on your way to sevilla, but staying for an overnight gives you additional time to explore beyond the mosque. granada is definitely not a half day destination, you need 2 nights min to see it. if you just want to see these 3 cities you don't need rental car, just use bus or train you'll be fine. parking is not easy, and most recommended hotels, for instance in sevilla, are in the santa cruz neighborhood, it's closed to cars.

Hi, we did a similar trip in March of this year and would highly recomend rail travel in Spain. Travelled from Malaga to Cordoba and spent 3 nights and then on to Seville for 2 nights . Trains in Spain are of a pretty high standard especially compared to the UK.
Also it was very reasonable cost wise .Check out the RENFE website.

No one base of these three could work for me, as Seville to Granada is three hours each way, whatever your transport. Even if you, let's say 'make good progress' on the highway, you will have unfamiliar cities to negotiate, if day trips, and will expend valuable time. Certainly Seville deserves more than a day trip and if wanting more than the Alhambra and a meal, so does Granada. You do not say where or how you enter the region, or for how long and intimate you are only interested in the cities. So thus far, I suggest you stay in Seville and take the train to Cordoba for a full day trip (less than an hour each way) and seems to suit most. As already advised train, or bus, to or from Granada and stay. The car is an unnecessary burden in any city.