I have walked from Granada to Cordoba. You can find my description here:
camino-mozarabe-and-via-de-la-plata/topic8801.html The first long distance before Cordoba is no problem. You make a detour to Santa Cruz. Its marked. People in Santa Cruz said in April 2010 that they had pilgrims staying there almost every night. I have not walked from Cordoba to Merida, but I have done some research about the second long distance. (Can not remember the names there now.) I have not found any posibilities to make it shorter.
About albergues, I think the albergues listed on Mundicamino was ment for others than the modern pilgrims. I wrote this on the question last year: "We slept in Hostales. There are almost no albergues. I think the parroqial places was not ment for modern pilgrims originally. The church helped poor people who needed a place to sleep by having those places. We have found that they are often closed now, may be because they were ment for other people than us. Relativly wealthy modern pilgrims - out for a modern walk - have may be done something to this institutions which is not all good? I am not sure of this. It is just a growing feeling from several years of walking." Bjørg