Take a look at Portugal Green Walks. They have a planned walk from Porto to Santiago that they will customize according to your wishes. They offer transportation if you need it. I did the Portuguese Coastal with a friend last year in May. I suggest cutting the walking miles per day to begin...
This site is run by Ivar at in Santiago de Compostela.
This site participates in the Amazon Affiliate program, designed to provide a means for Ivar to earn fees by linking to Amazon