Howdo Gyrus,
Galicia, you lucky bugger. I've not been to Galicia but if I were to go there, apart from the beautiful rock art I would also check out a few of the hundreds of castros over there. Some of the decorated slabs of the sauna baths over there are outrageously carved.
http://www.uwm.edu/Dept/celtic/ekeltoi/volumes/vol6/ 6_3/gonzalez_ruibal_6_3.html">http://www.uwm.edu/Dept/celtic/ekeltoi/volumes/vol6/ 6_3/gonzalez_ruibal_6_3.html
http://www.uwm.edu/Dept/celtic/ekeltoi/volumes/vol6/

Coincidentally or maybe not there was a La Coruna was once called Brigantium.

It also may be worth asking Julian to put you in touch with Annexus Quamm

It probably isn't where you'll be going, but I've just been to Valencia, and they've got the most excellent modern museum of prehistory. Everything is beautifully explained (pictorially, I couldn't read the Spanish). They're mad on actually making things to find out how they were made, so there are modern axes with all the flakes carefully attached so you can see the process. Also pictures of how things like fish-hooks were actually used. So refreshing from the dusty prehistory galleries in this country.

Most fantastic of all were the Palaeolithic carvings of animals. Just amazing. With just a few lines the artists completely captured the movement and dignity of the animals. The ridiculous security guards got in a state when I started drawing them and eventually (me with no Spanish, them with no English) I got to speak to the curator, who said it was fine to draw them (naturally) but that you need a permit to photograph them. So much for the laid back Mediterranean culture: my eyes have been opened. (But all that's by the by). I strongly recommend the museum.