Maria's place is easy to find - we followed the advice of a previous guest and caught the 602 bus from the airport to Cordoaria. It really is very easy to find from there and I think the bus cost us 2euro each.
The apartment is as appears in the photographs and is well located to take in many of Porto's famous sights. The shower is great and we appreciated being able to cook occasionally, although as others have said there are lots of great restaurants very close by!
One thing to note is this location is unlikely to be suitable for people with mobility issues. The apartment is on the top floor with no elevator - this was fine for us - but outside is very hilly - that is why the views are so great!