Ronda and Arcos each for 2 nights or Ronda for four?

The hilltop at Arcos is wonderful at night and early morning. I remember waking up and looking out my window to the thick morning clouds covering the valley below. I didn't spend a night in Ronda but I expect similar views would be possible. I don't know whether a 3-1 or a 2-2 split is better, but I wouldn't do Arcos just as a day trip if I had four nights total. Arcos is closer to Jerez and Cadiz, if either of them interests you as a day trip destination. But Ronda is bigger with more to do over multiple days and nights.

ViaMichelin.com estimates the driving time to Arcos from Seville at about the same as it is from Ronda--roughly 1-1/2 hours. The direct drive from Seville to Ronda will take at least 2 hours. Rather than treating Arcos as a day-trip from Ronda, I'd plan to see it on the way from Seville to Ronda. I believe that would give you plenty of time in Arcos. I agree that Ronda has a lot more to see, so I'd prefer to make it my base for the white towns. Although the populations of Arcos and Ronda are not all that different, Ronda felt considerably larger to me--I guess because its sights are more scattered.

If you go to ViaMichelin.com to plot your driving routes and zoom way in, the most scenic roads will be highlighted in green. I see there's a good bit of green along the Ronda-Arcos route that goes through Grazalema. It's a bit slower than the fastest route, which follows an arcing path to the north. Grazalema is worth a stop if you have time en route from Arcos to Ronda. Grazalema's a lot smaller than Arcos (about 1/15th the size in terms of population).

You didn't ask, but: If I had twelve nights available, I would not split them as you are doing. Seville is a large city with many (and somewhat scattered) sights of interest. I think the city itself could use an extra night. If you aren't also spending some nights in Cordoba, I'd definitely want to take a daytrip there, which would call for an extra day. Seville to Cordoba is a lot faster by train than by car. If you drive, there are at least a couple of attractive towns along the way--Carmona (which I have seen) and Ecija (which I have not). You can Google for photos to see whether they might be of interest.

Although I like Ronda, I'd trim the time there to make room for Cordoba. Four nights is quite a lot of time for Ronda plus the white villages.

As for Nerja, I'm guessing you're hoping for some beach time there. Otherwise, four nights is a lot when there are so many other attractive destinations in southern Spain (including Cadiz and Malaga). Nerja finally has a sewage-treatment plant (guess where the sewage used to end up?), but I haven't been able to find a recent article about how it's working out. I'd recommend checking locally to be sure it's now clearly safe to swim in the ocean there. Here's an old TripAdvisor thread discussing the situation prior to opening (earlier this year) of the plant: https://www.tripadvisor.co.uk/ShowTopic-g315917-i5571-k12857308-NerjaSeaWaterQualitySafe-NerjaCostadelSolProvinceofMalaga_Andalucia.html

So are you not going to Cordoba or Granada? In that area of Spain, Sevilla, Cordoba and Granada would be my priority. I would be hard pressed to find enough to do in Ronda for four nights. Its stunning, for sure, but it was not my favorite of the white villages. It was quite large. Now, for us, the gorge paths were closed due to heavy rain which surely impacted our enjoyment of the town. I found Arcos, Grazelema, Zahara and Setenil much more charming. Arcos is fairly large, as well, but we really enjoyed the limited time we had there, if we had the time, we would have stayed overnight in Arcos. We did Arcos on the way from Sevilla to Grazelema, we also stopped at Zahara prior to getting to Grazelema for the night. We got to Grazelema well after dark. The problem with lodging in Arcos or Ronda is that each is pretty much on the edge of the white villages, so neither is very central for day trips.

If you're an experienced, efficient traveler I'd go for 2 and 2. Ten years ago we spent 3 nights in Ronda and enjoyed it. Haven't visited Arcos.

Thanks for the input.
--Nerja seems appealing, mainly because I think some down time in the middle of the 30+ days could be beneficial. We also want to do a day trip to Frigiliana from there. That being said, I think I will cut one night from there and add it to Sevilla. (And yes, we are also spending multiple nights in Granada and Cordoba.)
--Two nights in Ronda and two nights in Arcos for the win!

Thanks to all for your feedback.

I've heard Frigiliana is quite nice! I saw a friend's pictures and they had a nice time there.

I would split them 3-1. With Ronda as a base you can explore many of the pueblos blancos easily. There are also quite a few sights in Ronda, including a couple quirky museums. My favorite is the wine museum which has a lot of folk displays and tastings. The bull ring is a must-see and its museum is excellent. You can usually find a Spanish guitar concert in the evening and there are some very good restaurants. I don't think there's nearly as much to see and do in Arcos.

I second visiting the bull ring in Ronda!

We started our 2019 trip to southern Spain in Nerja for 3 nights and really enjoyed it. Went to Frigiliana for 1/2 day plus and it was a lovely place to wander around, enjoy a meal, etc.