Seeking driving tips from Santillana del Mar to Santiago De Compostela

2 tips.
Be sure you bring an international driver's license with you. This needs to be purchased in your home country. If American, then the AAA office can sort you out.
Second tip, particularly if American, don't expect any leniency over the posted speed limit despite the speed of traffic.

Yes, be sure to stay as close to the speed limit as possible. I got a traffic camera ticket outside of Melide heading towards Santiago at mile marker 86.4 on the N-547. If you get a ticket, you'll receive it in the mail about a month after you return from your trip. Pay it promptly and it is half the stated €100, so it's only €50.

There are only a couple ways to get from Santillana to Santiago.
1. Take the A67 south - to the A231 - to the AP71 (toll road) - to the A6 - to the A54 which runs into the N547 to Santiago.
2. E70 west to Gijon then south on the AP-66 towards Leon then to the AP71 (toll road) - to the A6 - to the A54 which runs into the N547 to Santiago.
3. E70 west to Vilalba to the A8 south - to the A6 west towards Betanzos, then south on the AP9 (toll)
Driving time will be about the same no matter which way you go.

When I was there in May, we drove the 3rd choice, but started in Santiago and went to Santillana. After going to the coast to visit Muxia, we drove and spent the night in Ribadeo. If you decided on either of the other choices, you could spend the night in Leon. If you felt up to it, you could continue to travel west to Ponferrada or Villafranca del Bierzo to spend the night. There isn't much to see in Ribadeo, but a lot to see in Leon (we spent 2 nights there). So, it depends on what you'd like to see en route.

Along the northern route we stopped in Picos de Europa to see Cangas de Onis and the Sanctuary de Covadonga. We also stopped at Cathedral beach near Ribadeo to see the beach. Along the other routes between Leon and Santiago are a number of places to see. We stopped at Obrigo to see the bridge, Astorga (cathedral and Gaudi museum), Ponferrada (castle and clock tower), Alto de Cebreiro (Celtic huts), Vilar de Donas (Church of San salvador), Melide (oldest wayside cross in Galicia). Just outside of Santiago is Monte de Gozo (monuments to the pope and one to the pilgrims walking the Camino de Santiago.) Most of the places between Leon and Santiago that I mentioned are on the Camino de Santiago and can be seen in the movie "The Way."

For most of our trip we stayed in Paradors (government run hotels). We stayed at one in Santillana, Ribadeo, Leon, Santiago, and Villafranca del Bierzo. Most paradors are in old and historic buildings and generally cost about a same as a decent hotel. Santiago is more expensive but right outside the front door is the cathedral. You may want to look into them and the Friends of the Paradors program www.parador.es/en.

Thank You very much. Your post was quite helpful

Day 1.
Check out a typical Asturian fishing village (Llanes, Ribadesella, Lastres) on your way to historic Oviedo.

Day 2.
Travel to Santiago de Compostela via the walled city of Lugo.

Viamichelin gives three route options, the coastal route being the fastest. Scenic roads are marked in green, but it appears that to experience those you'd have to deviate from VM's routes. The Picos de Europa area is lovely. I enjoyed a couple of hours just wandering around the extremely picturesque old stone town of Potes.

Northern Spain tends to be cool and damp even in mid-summer. Plan for a lot of overcast or rainy weather. It's possible that there would be somewhat more sun if you took the southern route.

Leon (southern route) is one possible overnight stop. It has a large historic district that (at least in summer) is very lively. I have no idea what the parking situation would be like. As I recall, the old town (also the restaurant/bar district) is heavily pedestrianized.

We did not find parking in Leon to be difficult. RS guidebook said Leon was not well signed and that was our experience. We don't use GPS, just maps and we were uncertain where to turn when we were driving through town. It seemed like we had gone "too far" so we turned towards the cathedral and went directly to the RS recommended parking lot from the east instead of from the south as planned. We were right by a pedestrianized restaurant area, very convenient.

We did Leon as a day trip from Astorga. I think Leon would be a nice place to stay. Astorga was very quiet, which is what we were looking for. We also stayed in Lugo, not a big tourist town but has a lively restaurant area and was a good base.

I think stopping places are well covered by earlier posts. A bit south and west of Ponferrada are some amazing Roman gold mines that we really enjoyed. We were there a few hours but you could make this stop in less time.

Eef's mention of the Roman gold mines has reminded me that I forgot to mention the prehistoric Altamira Cave very near Santillana del Mar. I believe you must reserve in advance to visit that cave. I was staying in Santander and didn't manage to get to the cave.