What time of year are you planning to take this trip?
Are you big art fans? If not, I think your Barcelona/Madrid time may be out of balance. Since Barcelona is your arrival point, 4 nights there gives you just 3 full, mostly-not-jetlagged days. Depending on how interested you are in the modernista sights there, you may have a hard time fitting everything in. Many of Barcelona's most popular sights require timed tickets, and you'll need to buy them in advance to avoid spending an hour or longer in line, and possibly encountering a sell-out. It's difficult to be an efficient tourist when you have to pin down so many entry times. You simply have to guess how much time you'll spend at Sight A and how long it will take you to get to Sight B. To be sure of not running out of time (entry fees for a lot of the Barcelona sights are over $20 per person), you'll be padding your schedule an will probably end up with scattered snippets of extra time that aren't very useful for sightseeing.
Madrid is a newer city than Barcelona, and one that a lot of us find not as interesting--aside from the magnificent art museums. People typically pad their time in Madrid to allow for side-trips, but you've taken care of one of those already, by planning time in Toledo as well (great plan). You still have Segovia, Cuenca, and some other options, but there's the wonderful Girona you could visit from Barcelona, which you won't have time for.
Seville is a lot larger than Granada. While there's nothing wrong with 4 nights in Granada, I have a feeling you'd find that 4th night more useful in Seville.
Cadiz is interesting enough, but--given that you obviously don't like to rush around--I think you may wish for more time in Barcelona.
Cordoba can be more easily visited between Toledo and Seville, or (if you don't go to Valencia after Andalucia) between Granada and your final night in Madrid.
I'm not sure what you mean by "Valencia/Ronda". They aren't in the same area at all, nor are they in the same direction from Granada. Ronda is sort of between Seville and Granada, and that's where I'd position it on the itinerary. Valencia is either a long bus trip (or drive) north of Granada or a time-consuming train trip by way of Madrid.
Although I haven't checked the train schedule, I think you'd do better to place Valencia between Barcelona and Madrid rather than between Granada and Madrid. The very atmospheric hill town of Cuenca is right on the AVE (express-train) line between Valencia and Madrid. Cuenca also has a couple of very nice modern-art museums. It's very much worth a day if you find you have time to spare.
Valencia is a pleasant coastal city, far less touristy than Barcelona--but (in my view) for a reason. You have time to include it in this itinerary, and it fits pretty well, geographically, but I'd suggest digging into a guide book or two and working up a list of the sights you hope to see in Barcelona and Seville before making a final decision about Valencia and Cadiz.
Although you aren't horribly pressed for time, you can cut one hotel change out of you trip by postponing all your Madrid nights till the end. You'll need to stay there the night before your flight home, anyway. It will be more efficient not to check in and out of Madrid hotels twice. You could go straight to Toledo (just changing trains in Madrid) and make Madrid your final stop.
I think this order might be best:
Toledo (changing trains in Madrid)
?Cordoba? [or after Granada]
?Cordoba? [or after Toledo]
This trip will be far faster by train than by car. Some visitors like to rent a car to cover the area between Seville and Granada--Ronda and perhaps one or two of the white villages (such as Arcos de la Frontera). Otherwise, it appears to me that a car would be an impediment. And you don't need a car if you just want to hit Ronda.