Hi, Urban Trekker,
I may have already mentioned this, but the online CSJ guide would give you some basics on distance between towns, etc.
http://www.csj.org.uk/guides-online.htm There is both a Lisbon-Porto section and Porto-santiago guide.
I was living in Lisbon for a while in 2009, and walked with a combination of day trips and a few three or four day segments. My stages are here
http://www.caminodesantiago.me/comm...camino-portugues-from-lisbon.5398/#post-37487
You might want to cut out the Lisbon - Alhandra section. Walk on day 1 to the Parque das Nacoes from the cathedral and then take the metro back to where you are staying. (Cathedral to river park is about 10 kms, I think). Day 2 take the commuter line from downtown Lisbon to Alhandra and then walk to Azambuja, where there is private accommodation.
Places to visit: Tomar and its monastery, Conimbriga (about 10 kms south of Coimbra, Roman ruins) and Coimbra are the high points. My picture up on the left was taken as I arrived in Gaia, the town across the river from Porto. That is one of the most beautiful "built environment" views in the whole country, without a doubt.
There have been new places opening up all along the route since I walked, you can find a lot of those threads here in the forum and they might help you shorten some of the longer stages. How many days do you plan to take, more or less?
Buen camino, urbantrekker! Laurie