Did the run from Lagos through Spain (100km from Santander) to Brittany, then Limoges region and then back to Lagos in the Algarve, a couple of weeks ago. 5000km in 10 days. Aaargh!
Have done this run several times in recent years, on me tod and with the other half who is an excellent co-driver.
If both of you drive Santander to the Algarve should be doable in +-11hrs. (Stops included)
We ran back from Le Moggies and overnighted in Northen Spain just outside Burgos. The next day we ran the full way back to Lagos in about 10hrs 30 mins - Both of us driving.
I have done the run from Lagos to Burgos myself non-stop and ended up talking Spanish to myself and overdosing on Tapas and Beer. You both need to drive to avoid insanity.
Recommended route to avoid tolls wherever possible, benefit from lower cost fuel in Spain and see wonderful country is Santander, Palencia, Valladolid, Salamanca, Caceres, Merida, Seville, Huelva, Ayamonte, the Algarve. It is Motorway all the way.
As regards security of the car, I always unload even if the car is in secure parking - its just not worth it in any country these days.
If you really want to stop somewhere with parking, there is the IBIS in Salamanca. (But its right in town and a pig to find.)
Near Seville, heading south towards Huelva and just behind IKEA, there is the Leflet Castilleja la Cuesta. Underground secure parking but the ramp is very very steep and there are only a couple of restaurants nearby. However, its reasonably cheap and v. clean.
