The suggested 30km stage might feel a bit long for some, especially if it's on day one. But I love that walk from the Ribeira straight out to the ocean at Foz and up the coast along promenades, coastal villages and boardwalks, a good feed of sardines and a cold beer or two from any number of places along the way. I've walked it more than a dozen times, sometimes just for something to do when visiting Porto.
If you plan walking it in one go, I would suggest (getting your credential and sello at the cathedral out of the way the day before) starting out at first light to enjoy it at your own pace.