Originally Posted by
sdsearch
Well, I don't know you guys, so I didn't know if you might need or want to go back to the hotel during the day!
How was I supposed to know that? 
So I wasn't telling you about hard it is to drive there because I thought you were staying there with the car, I just wanted to point that out in case you were considering going back to the hotel while you had the car.
I don't think you can get to any of the locations with old windmills without a car (or perhaps tour buses, rather than normal buses), even if that's the only thing you want to see. They are a couple hours south of Madrid on various lonely roads. At one of them (but only at one, and not the best one in terms of authentic age) I saw some sort of tour buses, I presume it's an all-day tour. Some of other locations didn't have places for tour buses even, just a dirt patch to park one or two cars at a time.
So it depends on what you want to see as to how much you need a car.
Exactly. Therefore stop making assumption if you are really trying to help instead of patronizing, then read more carefully before posting a reply.
If we plan to return to the hotel during the day, we would choose to stay in town, instead of at an airport hotel. The purpose to choose an Airport Hotel with shuttle service or easy public transportation to get to town is obvious. I thought it is just plain common sense. After all, who in his right mind would drive from Airport hotel to town for a few hours and then drive back to the airport hotel, only later to drive out to town again? But as the old cliche says, common sense often does not seem that common!
Sorry, no idea about what "old windmills" meant. Forgive for my ignorance. I thought if you want to see authentic old windmills you go to Netherlands... They are not on our radar. Besides, have seen enough of such stuff in The Netherlands and on Greek Isles (literally stayed within 3 min walk to 5 such old windmills on Mykonos), not by designed but just happened to see them. Good enough for us.
Our road trip covers a much broader area far from Madrid - go north to Santander, down to Leon, and go east all the way to Santiago de Compostella, and back via Salamanca and Avila. Doing zigzag along the way, depends on how difficult/interesting to explore Pico de Europa National Park. Could also go to Aranjeuz, South of Madrid, if we have time left.
Now if you and anyone has covered any of the above places, then your insights would be very helpful and relevant.