FINALIZING SPAIN & PORTUGAL - MAY 2016
 

with a lot of great advise from fodorites and research i'm ready to start booking our trip. flying in and out of madrid may 9 to june 9 renting a car as we leave madrid. not too interested in big cities.
3 days in madrid (explore + day trip to segovia)
4 days in antequera (day trips to granada, cordoba + explore the countryside)
4 days in western andalucia (maybe jerez)
3 days in alentejo region of portugal
3 days obidos (day trips to lisbon, sintra)
3 days in douro valley - peso da regua as home base
3 days galicia - lugo or small village along the coast west of santiago de compostela
2 days asturia coast - lianes ???
3 days in small town between bilboa & san sebastian
1 overnight at hotel at madrid airport

thank you in advance for your help

Why not just fly out of Bilbao? You can make your connecting flight in Madrid instead of traveling back to Madrid just to spend the night.

i'd rather have another day to see more of the spanish countryside. much better than more time in an airport. also the price of 2 tickets and the extra fees for not returning the car to madrid seems to be unnecessary expenses. but thanks for the thought.

When in Antequera, perhaps walk the newly restored and upgraded (ie. safer/safe) Caminito del Rey: http://www.caminitodelrey.info/en/#3

Regarding countryside, the San Sebastian countryside is quite spectacular immediately both east and west of the city itself over respectively Monte Ulia and Monte Igueldo.
https://en.wikipedia.org/wiki/Mount_Ulia
http://www.lonelyplanet.com/spain/ar.../monte-igueldo

Are you sure you would face extra fees for not returning the car to Madrid?

i haven't checked about the fees but usually there is a charge

When I was in Spain in May, I didn't face a charge for dropping off in a different location than where I picked the car up. In fact, I've rarely faced such charges outside the U.S., unless the pick up and drop off are in different countries.

Never heard of extra fees to drop off a car in a different location within the same country. Sometimes extra fees for good locations like airports.

Typically, within the same country, the additional fees are for picking up at the airport or train station, not dropping off at them.

I just checked on car rentals with autoeurope and it depends on the rental company if there is a one-way charge ($56) - Avis charges, Hertz did not - but the rates were very comparable. In 3 months I am doing 4 different one-way auto rentals so I had to find that out. I remember the days when it would cost close to $200 to do it that way.
Good luck!