I am planning on spending around 3 weeks in northern Spain, but starting out in Barcelona.
I'm just not sure whether it would be better to drive there from Barcelona or take the train.
Is there anything really interesting to see en route, if we drive?

As for the northern coast, I would be interested in fun, charming and historical locations that we can either take day trips or spend a little more time.

As of now, the itinerary is wide open.
I would welcome any suggestions.

What time of year is this trip?

May 2012

From Barcelona to the Basque country is an inland drive at the base of the Pyrenees. Nothing coastal about it. The coastal drive would be from San Sebastian on to the west.

These pictures cover our trip between San Sebastian and Barcelona--for you in the reverse order:

http://www.flickr.com/photos/mksfca/...7623190654780/

Most of them are geo-tagged to give a sense of the geography.

you may want to take a look at my blog as a local on the Basque Country, for off the beaten track places, www.blogseitb.us/basquetourism

Drive through the beautiful Pyrenees from Barcelona to San Sebastián on the Atlantic coast. Perhaps use a couple of days and stay overnight in Torla. http://www.uniquespain.com/torla.html

San Sebastián would be a perfect base for exploring the Basque country. The culinary capital of Spain if not all of Europe, great beaches, beautiful landscapes and a living culture that people take great pride in.

A recent article about San Sebastián in New York Times: http://travel.nytimes.com/2011/08/07...tin-spain.html

The article "A different kind of Spain" gives you an idea of San Sebastián and the region: http://marshlands.blogstream.com/

All the following would be perfectly doable as day trips (small distances), but perhaps stay overnight a couple of places?

Go inland to Tolosa (here you can have the best steaks in the world), the old university town Oñati or the Aranzazu Monastery.
Oñati and Aranzazu: http://en.wikipedia.org/wiki/O%C3%B1ati

Lots of charming small fishing villages along the beautiful coastline between San Sebastián and Bilbao: Getaria, Zumaya, Mutriku, Lekeitio etc. etc. Fabulous food all along the way, had the meal of my life in the harbour of Getaria in the mid 90's.

Bilbao is a great city that should be visited not only for the spectacular Guggenheim museum: http://www.guggenheim.org/bilbao

For historical sites, you should visit the town of Gernika/Guernica (Picasso's painting) close to Bilbao. Destructed by German bombers on the 26th of April 1937 during the Spanish Civil War. http://en.wikipedia.org/wiki/Guernica_(painting)
Picasso and Guernica: http://www.pbs.org/treasuresofthewor...n_guerfrm.html

Explore mikel's great blog! I have also a lot of more detailed tips, have lived here and visited almost every year since the late 80's.

And, finally, all about going for the world famous pintxos in San Sebastián: http://www.todopintxos.com/home/home.php

I would read some guidebooks, review blogs and sites mentioned above and then come back with more specific questions. Northern Spain is a huge and diverse area, the Basque Country just one of the many places you could visit.

Also check out Maribel's guides - they are excellent for both Barcelona and the Basque country.

maribelsguides.com

You can click on my name to read my trip report from October 2011. We spent 5 days in Barcelona, then rented a car for a 3 night/4 day road trip along the Costa Brava, through some of the Pyrenees & Girona. We only had 10 days. If you like what we did, you could follow our route, then continue on through the Pyrenees (beautiful scenery) to San Sebastian.