Suggestions for small town 'feel' itinerary

Look at Zamora, Avila, and Salamanca...Also Segovia. Santander on the coast is also very nice.

Segovia, mentioned by H J is easily accessible from Madrid by bus and/or train. For history, it has the Alcazar and the Aqueducto in town, and La Granja palace just outside of town. For food, it's the epicenter of cochinillo, roast suckling pig. For music, the region has its own instrument, an acquired taste that sounds like a cross between an oboe and a kazoo, and a shop in town this past November had CD's from some popular local musicians. The salesgirl played several passages of tunes for us and explained the social importance of the instrument and that music style. A small population of Bulgarians has recently moved into town, and the Bulgarian woman at the desk at our hotel mentioned there was a Bulgarian communtiy center in town, but we didn't get a change to check it out on this trip.

Buses go from virtually anywhere to virtually anywhere. They're used much more than trains in Spain, so getting to small towns really won't be a problem. The biggest problem with any public transportation choice is valuable travel time lost to connections.

In your amount of time, I'd probably stick to Northeast area (since you're already in Barcelona).

Montserrat would be good, there are lots of day trips by bus from Barcelona (the TI or information booth at the bus station should be able to help you find one), not sure about getting there by bus then continuing west.

Toledo, Avila and Segovia aren't bad choices. If you go there, maybe add Cuenca on the way.

Another option is to head north from Zaragosa toward Pamplona and San Sebastian, then back around toward Barcelona (through Figueres). If you go that way, I love the castle in Olite (about 20-30 minutes before Pamplona off road from Zaragosa). You can also visit St. Jean Pied de Port across the French border from Pamplona (the start of one pilgrimage route to Santiago de Campostela).

I know your already have enough stuff to see and do in Barcelona and environs, but I'll add one more - Girona. The guidebook I was using at the time described it as "a world class city patiently waiting for the world to notice" and they were 100% right. It has Arab baths, a Jewish quarter, loads of atmosphere - everything except tourists.

You could have a very good trip sticking to northern towns. If you're up that way, then Santillana del Mar is the epitome of quaint or Hondarribia has a nice historic center, both reached by bus from San Sebastian. In cities like Burgos and Leon, it's pretty easy to focus just on the historic center and ignore the rest of the city.

When you go to visit Figueres, try to go to Cadaqués (fishing village where Dali's house is) and Pals (small walled town with few people know).

Barcelona is so close to Cadaques and Portlligat it would be a shame not to go there. The only problem is transport: Figueres is easy VIA the train and the Dali museum is ok but the epitome of small mediterainean fishing town is the Cadaques/Portlligat area and the bonus is the Dali house which ended up being much more of a must see for my wife and I than the museum: but there is only one bus per day. We drove a rented car (with our own GPS) and its about a 1hr 30min drive. Once you are there you'll be wishing you were spending the night. On the way there we had the pleasure of seeing an open field in the countryside filled with sheep( I estimate at least 300) being herded by 3 dogs without a human in site!