I vote for the Norte-Primitivo combo as I habe heard the first half of the Portugese is so so while the first part of the Norte and the whole Primitivo are very nice, including some "cultural" stops in cities like San Sebastian, Bilbao, Santillana, Oviedo and Lugo, and some lovely ocean views and stunning mountain walks.
There is one guide I know of in English published by Cicerone, it is available on Amazon. I also used a Spanish Guide and a German one for the Norte, edited by Rother. I do not speak German but love its detailed maps, although really did not use it other than for liking to see where the road went, where I was in relation to other towns, not for walking directions. The Cicerone book also has a web sidekick by the same authors. It was just posted on the forum but alas I cannot find it now. If you van manage a bit of Spanish I recommend the book by Editorial Buen Camino. There is also info on line at the Gronze and Eroski web sites. Forwalk.org is in English.
Oh, and I thought I would add I walked on the Norte in September of 2015 and it was very hot: up to 34C. Unsual of course, but I think so was the freezing rain you experienced.