Hi Annie!
And first of all all the best for 2012 to you and all the pilgrims of our forum!!!
I walked indeed the mountain section between Irun, Hernani, Bidania and Zerain.
But after Puebla de Arganzon I did not go towards Haro and Santo Domingo, but towards Miranda da Ebro and Burgos.
So, mainly, I opted for alternative ways and not the most frequented ways on the Tunnel Route.
Even there, the waymarking was quite good most of the time. I just had at several occasions some troubles seeing the marks... But every time, I finally found my way. And I was not so very good prepared : it was my first camino "off the beaten track", but had no compass, no maps with me... Only a German guide book (old of some years and so not always very accurate) and the booklet of the Basque Tourist Information.
I mostly remember that in the Basque Country there were 2 kinds of waymarking : yellow arrows and wooden posts, the first from the local association, the second from the Tourist Board. At some points, they did not correspond one to another - creating some confusion in a poor pilgrim's mind...
As to the second part, from Miranda da Ebro to Burgos, there were yellow arrows. And in the albergue of Puebla de Arganzon, there was a little information leaflet about that way. Beside two or three times I cannot remember bigger problems finding my way...
- in the fields after Pancorbo : I nearly missed one arrow because of huge vegetation (the way followed the railway truck for some time and at some point you have to cross a bridge and continue through some fields). By the way, at some point, there were no arrows but yellow plastic straps to waymark
- between Monasterio de Rodilla, after the "wind park" and just before the Roman road : in the woods, one arrow was pointing in the wrong direction
- after having left the Roman road, some km before Burgos - I missed an arrow at the end of a very long day
The only part that was really "hard" was between Briviesca and Monasterio de Rodilla : several times, the way was alongside a very frequented national road...
Tell me if you need more information!
This way was absolutely gorgeous, beautiful, lonely, lovely and great!
And the Spanish people very helping and open minded!
BUEN CAMINO
NB The Basque Association seems to be very active, so plenty of things might have changed since july 2010...