5 days in Basque Country

Use ViaMichelin to get driving-time estimates from potential base cities. Distances are not terribly great. I traveled by train and bus (but not on the French side of the border) so don't have a great sense of what would be most practical for car travelers. The Basque countryside is lovely, so I'm very glad you don't intend to spend all your time along the coast.

San Sebastian might be a good choice for Base #1. From it you can visit Hondarribia (fishermen's district with restaurants, upper-level medieval district), Bilbao (Guggenheim, Bellas Artes Museum, Casco Viejo, a Calatrava footbridge, and some nice early-20th century architecture in the "downtown" area), and a number of charming costal towns--former fishing villages that have now been developed for tourism. The coastal towns I visited were Zarautz, Getaria and Zumaia, all west of SS. Farther along the coast toward Bilbao is Lekeitio, often mentioned in guidebooks but unvisited by me. While in Bilbao I went to Bermeo, which I also liked.

Try to allow a full day for Bilbao if you plan to visit the Guggenheim. It's a pleasant walk from the museum to the Casco Viejo, and the historic area is quite large. Bilbao's less touristy than San Sebastian, and I actually preferred it. It lacks the center-city beaches, though.

Although you will have a car, some of the excursions from SS might be simpler by public transportation, depending on the difficulty of finding parking. There's very frequent bus service to Hondarribia, for one example. The narrow-gauge FEVE train between SS and Bilbao goes through really nice scenery (it takes an inland route), but it's an incredibly long ride. If for some reason you don't want to take your car to Bilbao, the bus is a much faster option.

If you want a city rather than a small town for your second base, consider Vitoria-Gasteiz, which is the capital of the interior region of Alava. It has a large, picturesque historic district and several interesting museums. Last year it was possible to get an English-language tour of the cathedral, which is being restored. From V-G you can visit the stunning medieval hill-top town of LaGuardia, which is very near the La Rioja wine country. I'm not a wine person myself, but I noticed multiple wine bars in Laguardia. If you prefer a small town for Base #2, I'd give serious consideration to Laguardia. I think there's at least one small 3-star hotel in town. Research the parking situation, though; you might need to park below and take the elevator up.

You didn't mention when you will be traveling. The Basque Country is considerably cooler and wetter than much of Spain (thus the green countryside). You are not guaranteed beach weather. I got rained on in San Sebastian and really rained on in Viktoria-Gasteiz in mid-June.

Edited to include ViaMichelin link in first paragraph.

We will be traveling in mid- June. Thanks for the advice on Vitoria and Laguardia. We are always looking for off the radar towns, and both sound lovely. Would you advise staying just outside of San Sebastian or in the actual town? I keep getting mixed signals on SS. Some people insist that it has become too touristy and others rave about the food and atmosphere. I love the idea of parking the car and taking public transport.

The last time that I was in the San Sebastian area with a car, I stayed in the old town of Hondarribia and found it relatively easy to drive in and out of (with hotel designated parking spot). But I was not visiting the actual city of San Sebastian on that trip (been once, not enough time) and am not trying to dissuade you from some time in the city.

A good place to start would be the Basque Country Tourism page.

We go to Gorliz Beach. It is nice and sandy and not super crowded in the summer.
If you are going inland, an interesting foodie place is Idiazabal Museum. The visit is 2.10euros.
With cheese tasting, 3.10. And visit, cheese, and a glass of wine is 4.10euros.

One thing you might want to be careful with is Fiesta days. The 23rd is San Juan, and in most places they have some kind of celebration. In Laguardia, for example, they celebrate San Juan and San Pedro. It usually goes from the 23rd to the 29th of June.

As Laura commented, Hondarribia is a good place to use as a base. The Parador is in an old castle/fortress.
From there you are not far from the caves in the Pyrenees. Zugarramrdi is a famous cave where the last coven of witches (who were burned at the stake) in Spain lived. You can also visit the Baztan valley. It is becoming popular because of the Baztan Trilogy, and really is quite beautiful.

And finally, I might suggest you think about Logroño. It is not as glamourous as some of the places, but it holds it own. The Local.es web sight said this:

Calle del Laurel

If you’re going to Spain for the tapas, why restrict yourself to the
well-trodden streets of Madrid’s La Latina or San Sebastián when you
can go to Spain’s little known pintxos mecca Calle del Laurel? Locals
in Logroño flock to this street day and night to meet friends and
drink late into the night. Logroño is the capital of La Rioja, one of
Spain’s most prolific wine regions, so take advantage of the delicious
tapas on offer by combining them with the local grape varieties.

and the Guardian said this

I would just add two things, you don't need a car at all, and Calle Laurel is very popular, but Calle San Juan is better. (and btw, the days before the 23rd this 100yd long street is in fiesta, in honor of it's patron.)

On Friday, June 24, 2016 I was in Laguardia and encountered a mini running-of-the-bulls. It was not like Pamplona--not people, just bulls. Baby bulls. It was cool to see. However, it was difficult to move around the town because of all the barricades, and I was afraid I was going to miss my bus. It all worked out, but I would have been better off if I had done just a bit of research!

I'm of two minds about San Sebastian. It's pretty, the San Telmo Museum is nice, I don't doubt that the food in the top-end restaurants is good, and it's pleasant to walk on the boardwalk along the beach. But the oldest part of the city is quite small and given over to bars, restaurants, and shops. It does get packed with tourists. Bilbao's Casco Viejo feels much less touristy, probably because so many people go to Bilbao and see nothing except the Guggenheim. As a solo traveler and a non-drinker, I didn't find the tapas scene at the mobbed bars in San Sebastian very enticing from the standpoint of atmosphere. It was hard to find a place to eat sitting down after 1 PM.

I wouldn't discourage a visit to San Sebastian, but I'd suggest making a point to see a bit more of the city, not just the small area between the tourist office and the San Telmo Musesum. The area across the river (channel?) is worth a wander, and the area south of the tourist office belongs mostly to the residents. Pl. Gipuzkoa (from which Hondarribia buses departed as of last year) is very pretty, and a bit farther south Prim Kalea and the area around the cathedral have a lot of handsome buildings (probably late 19th/early 20th century).

Edited to add:

About parking I cannot advise; I'm always looking for a bus or train. The historic areas of Spanish towns and cities tend to be pedestrianized, so you may need to do a good bit of walking after finding a parking place.

In Hondarribia, incidentally, the tourist office is in what seemed to me an odd spot vis-à-vis where the bus dropped me off. This is a town for which it might be nice to print out a map before leaving home. As confirmation that San Sebastian does, indeed, get a lot of tourists, its tourist office has some sort of contraption on the outside wall of the building that prints a map of the city. I've never seen such a thing, but it's a great idea for folks who arrive when the tourist office is closed.

acraven perfectly covered the north coast of Spain. While I haven't spent a lot of time in Basque France seeing all the small towns, you may want to visit St. Jean Pied de Port. It's very small but is the location in France where many pilgrims begin their trek on the Camino de Santiago. It's worth a couple hours. If you're Catholic, then Lourdes is a nice stop. The town itself it very touristy, but one can walk past to trinket shops go straight to the church and the grotto where the Virgin appeared. Bayonne has nothing of particular note but is known for chocolate. As a side note, after crossing into France there are some beaches between St. Jean de Luz and Biarritz. In Spain, one will see some topless sunbathers at some beaches, but in France almost all the females go topless. If you don't want your children to see nudity, you may want to be selective on the beaches you visit. Last, and this may be too far away for where you are going, there is a wine route closer in towards Bordeaux that goes past many vineyards including Lafite Rothchild where tours can be booked.

On my upcoming trip to northern Spain we are skipping SS and staying at the paradors in Santillana del Mar and Hondarribia.

Thanks for all of the great advice, especially the tip about the feast days. We are now thinking of staying either to the west of San Sebastián- we are looking at Getaria and Zumaia or inland at LaGuardia. Has anyone visited San Juan de Gaztelugatxe? It looks beautiful in pictures- but I am wondering if it is a weather dependent trip...
One last question- can Bilbao be done as a day trip? We would like to take a train or bus into the city. Any advice on what is better?
Thanks

Consider Getaria. I think it's about a half hour drive from San Sebastian/Donostia. Great beaches, scenery, food and architecture. We ended up there by accident a few years ago and now we can't wait to go back.

I think you could squeeze Bilbao into a day. Where would you be traveling from? There is train service to Bilbao but often bus works better; it just depends.