Help with itinery for northern Spain in late September

Day 1 San Sebastian
Day 2 Pamplona
Day 3 Santander via Bilbao (Guggenheim)
Day 4 Oviedo via Santillana del Mar & Comillas (Gaudi)
Day 5 Oviedo
Day 6 Santiago de Compostela via a Coruna (Hercules Lighthouse)
Day 7 Santiago de Compostela
Day 8 Leon via Lugo (walled city) & Astorga (Gaudi)
Day 9 Toledo via Salamanca
Day 10 Madrid
Day 11 Madrid
Day 12 Madrid

Thank you very much for your assistance. I looked up some of the places you listed and they are very interesting and the scenery looks inviting.

I took a similar trip a few years ago and one of the highlights was an overnight stay at the Parador at the Picos de Europa. The drive from the coast, through the canyon was spectacular as was the view from the mountain peak after the gondola ride. There's a nice free museum on the the route as well. Nice back door experience.

What kinds of sights are you interested in?

Pamplona is an okay town, worth a quick look (maybe a night). I really like Olite, which is about a 30 minute drive south of Pamplona. The castle there isn't one of the biggest but it's one of my favorite to visit anywhere. It's partially ruin, partially restored. They haven't furnished it, which allows you to roam at will, climb towers, go up or down stairs, with an audio guide that describes what the place was like when the Kings of Navarre (part of Spain and part of France) lived there.

St Jean Pied de Port is a really nice small town that is one of the starting points for the pilgrimage to Santiago de Compostela. Since you are going there later, this might be an interesting stop. Pamplona also has brass shells imbedded in the pavement, where the pilgrimage route cuts through town.

Vitoria, is the wine capital of the Rioja region. It has a small center that's worth a look. If you want to visit a Bodega in the area, however, you have to call ahead (two days is best) to let them know you're coming. Some places have wine museums, these are converted Bodegas and are more likely to have regular hours and/or the TI/your hotel will call and someone will open it for you.

If you go to Santiago de Compostela then back to Toledo there are a lot of choices. Salamanca has a great cathedral, Burgos is a great city - as is Valladolid. Valladolid also has three major castles in the area Coca, La Mota and Penafiel. The first two are monsters, the third is like a ship that sits on top of a hill (admission to Penafiel includes admission to the town's wine museum).

From any of these to Toledo, with a car, you can drive for a view of Avila (the area called "four posts" is considered the best view) then stop in Segovia for a few hours. Segovia is one of the few places where a Roman aquaduct, Cathedral, medieval center and castle can all be visited in a half day. Segovia also has a Templar vintage church just outside of town (worth a quick stop if you're driving, a little too far to walk to if you're not).

Toledo was the capital before it moved to Madrid. I consider Toledo to be effectively the old center Madrid is missing. It's my favorite "twisty street" medieval center in Spain (which is saying a lot because there are quite a few to choose from).

Personally I'd skip Madrid because I like history and it's new compared to anything in Spain. The El Prado gallery is one of the best in the world and should be on your list if only as a day trip from Toledo. The train from Toledo stops at Atocha station, which is about three blocks from El Prado; even with a car, I'd use a train for this.

We visited San Sebastian in April. It's a really nice town but is clearly best visited during the high summer months. In April (and possibly in September) it was rainy and chilly. Santandar gets great reviews. Like San Sebastian, it's a beach town. If the weather forecast looks iffy, you might plan another option.