Car rental is not particularly expensive in Spain and can be quite easily arranged on-line through AutoEurope here in the States (Maine, I believe). Their staff is extremely friendly and helpful. We've used them twice--last year in Italy, this year in Spain.

Although I don't advise driving in the big cities, especially Madrid (and didn't we hit a detour in the city during the evening rush hour when arriving from Toledo? duh!), it's great to have a car for exploring the countryside and small towns en route. It's generally easy to find a free parking place on the edge of town (like near the Aqueduct in Segovia or by the Puente in Toledo) or sometimes near one of the other famous landmarks (like the Alcazar in Segovia). Even in little Trujillo, Joe (the consummate "squeezer inner") was able to coax our Renault Scenic (great vehicle...an unsolicited upgrade, I believe) into a tiny space on a sloping side street. (The Plaza was in the midst of a "remodel.") Arriving in Caceres (absolutely gorgeous old city/town--more later in Favorite Places) on a Sunday morning landed us a parking place in the Plaza Mayor with so-called "guarded parking" for "a few" pesetas. We then, of course, spent the day having coffee at a plaza-side cafe, sightseeing on foot and enjoying a lovely afternoon dinner on the Plaza. (Great people watching--no extra charge!)

In Vittoria, we parked for "the day" in a parking structure (marked on our map) for a fraction of what it would cost us here at home. We then plodded through this beautiful city on foot--the only way to see Vittoria.

Of course, if you're traveling "solo," it wouldn't make sense to rent a car...as you need both a driver and a map reader. (Guess which is my area of expertise??)

P.S. Just remember to keep your belongings out of sight or, better yet, take only what you need.