Is Driving from Toledo to Sintra possible in one day?

As we have never driven anywhere in Europe, we cant advise as to routes and inconveniences. We can tell you that 6 hrs of driving (if that is ALL you actually spend) is a lot. Unless you have a place in Lisbon or Sintra already, you should set out early in order to arrive early, This lets you rest, then enjoy Sintra and later get your rooms and meal

Check out http://www.viamichelin.com/viamichelin/int/tpl/hme/MaHomePage.htm. Much more reliable than mapquest.
6 hrs is a lot of driving unless you are going to
stay in that area for a few days. It depends on
the time of year as to how long it will take you.
There are some interesting places to see on the
way.
You will be driving thru desert and mountains.

Thanks.
We would leave Toledo early on September 11.
My wife has to fly home September 13 from Lisbon.
We will already have seen Lisbon and want to spend September 12 seeing Sintra.
We would be staying in Lisbon and taking the train to Sintra for the 12th.
I know 6 hours is a pain but if we left at 8 or so we would be in Lisbon mid afternoon.

Stew....once you traverse the two-lane road between Toledo and the A-5, you're on four lane divided highways right through to your destination....A-5, A-6 and A-2,...all with 130 kph speed limits. Much of the A-5 thru Spain is a toll highway though...tolls should be about 15 to 20 Euro total.

Sorry Stew....typo...120 kph speed limits.