In reply to Batcloud:
Sorry for a bit late reply. Don't know much about cycling but judging by the numbers of folks cycling here in Spain you should be fine on whichever country road as most transit traffic goes via motorways.
That said, about specific recommendations: make sure you don't miss Cuenca. Guadalajara is nice and then northwards you have really nice roads leading towards Soria. If wine is your thing, a visit in Logrono is a must!
Out of these three, Cuenca is surely a must see!
Cheers
RS
Post edited at 22:57