Visited Costa del Sol long long time ago. We were there in Summer time - it was nice but very congested due to the time of the year - school holidays, so lots and lots of European tourists, esp those from UK.
Barcelona is not in the South - and generally has to go thru Madrid from U.S. I haven't looked into any details yet on our itinerary. I do know if we go, Madrid would only be a gateway as we had spent 10days in Madrid and its environs few years ago, so we would like to skip Madrid if we could. From Barcelona we would head South, Seville looks like a good place to be our base city - and we can visit Cordoba, Granada, etc from Seville... After that we then head for Portugal. Li*****on would be at the end of the trip. It is all just a very rough idea. Will look into it after our return from Australia in May.