I'll be doing the same next year...envy thy name is CaliBasco:

La Coruña is good, but urban. If you get out to the Torre de Hércules, it's a little more quiet. The torre is a 2nd C. lighthouse.

We've visited the Pazo de Oca, which is a small manor house (it kind of reminded me of a Gallego Versailles, only much smaller, much more wooded, and WAY less crowded. We were the only ones there the last time I went, and that was in the summer...Here's some info: http://www.webalia.com/viajes/galicia4.html
It's definitely worth the side trip. There's even a stone boat that floats in the back garden area.