Next summer I will go to St. James from Madrid, I made this trip once and it was amazing,worth it, the route start from Madrid,cross Castilla following the Castilla Channel to join with the French Path in Fromista ,from there to Santiago I will follow the traditional way, the most beatiful from me point of view.
The whole trip is around ten days because there are 650 kms from Madrid ,but depend about your bike's skills or your way of travelling,anyway is very interesting because you can get differents experiencies about landcapes,towns,monuments,etc....
Well if somebody are thinking to come to Spain next summer in order to make the Camino de Santiago this is another option to do it.
For more information or even to join me you all can contact with me in me private email.