I understand that if I take a train from Santiago to Porto that I will need to transfer at, or near the border of Spain and Portugal. I am a bit confused about the transfer point. In "Spain 2013", Rick mentions transferring at Vigo, or Redondela. The confusion that I have is that there are Renfe & DBahn listings for "Vigo-Guixar". Does anyone know if this last one is the actual transfer point, and is that the location I should plan for when purchasing tickets? Thank you
Vigo-Guixar is the correct station. You don't have to tell DB the connection points you prefer. If you search between your start and end city, if gives you a schedule with recommended connection points. Although connections on that route are still poor, they have changed a bit. The 7:30 a.m. departure (for my test date) has connections at Vigo and Valenca (with layover), or the 17:30 departure only changes at Vigo.
Vigo-Guixar is the new station so the guide book is a few years out of date.
P.S. Portugal book researchers had their work cut out for them this summer. A few book updates are currently online at http://www.ricksteves.com/europe/portugal/guidebook-updates, but the book that comes out in March will have many more changes.
They may have there work cut out but the changes to the railway station are applicable to Galicia, Spain. Just read the bit about toll roads, it is not that simple to make payments after crossing the border. Good luck with the rewites!