Can anyone suggest a 5 day itinerary for Porto and within say 75km radius of Porto.
Also any thoughts about renting a car, or can everything suggested be done by train etc?

thanks

Porto itself requires min. 2 days but I could easily spend a whole week there.
Reserve a day for the Douro Valley (vineyards). I think this can be done by train but we always rent a car abroad, so we drove the valley, all the way along the Douro river, upto Pinhão. It was a very, very scenic drive. If we would have had more time, we would have loved to spend a night on a working quinta in Pinhão.

Another day excursion from Porto is Guimarães (and Braga).

You can take a train up the Duoro valley, although the mountain railway branch lines I took in 2004 no longer operate. I also like to take the train to Braga.