Convince me which way to go

So you have been to Barcelona before, but your travel partner has not?

Have either of you been to Bilbao before - or for that matter, anywhere else in Spain?

Barcelona certainly has easier/better connections, and would be the obvious choice for many, unless you've "done Barcelona" enough.

I've been to Barcelona, I don't think he has. I'm not opposed to it. I'd love to see Sagrada Familia but know how tickets are to get there. The other Gaudi stuff I could take or leave. I'd rather see new stuff, but it was cool the first time and I am sure I'd enjoy it again.

Neither of us have been to Bilbao. We've both done Madrid before, I've done the "big" southern cities (Cordoba, Sevilla, Granada, etc.) which we know we don't have time to visit this trip. I've also done Segovia (my favorite) and Toledo. We don't really have an agenda. I am not opposed to a beach visit, not sure his opinion.

How do you do in the heat?

The Atlantic coast in the north would be cooler (it's beautiful, too). Madrid's gonna be pretty warm, Barcelona too to a lesser extent.

San Sebastian was great!! Lots of little pintxos bars that were so fun and yummy! It was chilly when we were there in March but summer you could go to the beach. Probably only a couple days there though... you could side trip to Bilbao (I didn;t but some in our group did and liked it).

I had fun at the museum in San Sebastian... something about Basque history.

It was a cool place, I really enjoyed just walking the streets and hitting the bars for snacks!

You can get advance tickets for Sagrada Familia... I recommend at opening, if you go to Barcelona...

Kim

Weather-wise I think the Basque Country is your best bet. I've only been to the Spanish side of the border. I'm not a bar-hopper and much preferred the less touristy Bilbao to San Sebastian, but you certainly should see both. The interior capital of Vitoria-Gasteiz is very nice as well. These coastal spots are also worthwhile: Hondarribia, Zarautz, Getaria, Zumaia, Lekeitio and Bermeo.

If you end up in Barcelona, see the relatively newly-opened Sant Pau modernista site. They are doing more advertising now, but I think you can still walk right up, buy a ticket and go inside. It's a multi-building site that also has lovely exteriors, so allow plenty of time.

You could also spend a few nights in Girona, which has a lot to see right in town and is also a convenient base for day-trips to Figueres, Cadaques and the small town of Besalu (with a fortified bridge).

I'd start by looking into transportation options. You won't want to spend an excessive amount of time getting from Agen to your interim destination, and from there to Madrid.

There's a third great side-trip from Madrid: Cuenca. Getting there efficiently and affordably means buying an AVE ticket early, while you can get the promo fare. The regiomal train is much, much slower.

There's also the pretty former university town of Alcala de Henares, which is accessible via frequent, cheap commuter trains from Madrid, even on weekends.

It’s quite a long journey. I’d attempt to minimise my transit times by breaking it up even more. Travelling by train from Agen ...
2 nights in Bordeaux
2 nights in San Sebastián
2 nights in Bilbao
2 nights in Madrid