Lili was a really great host. She had tons of information and recommendations for us in regards to places to visit, food and restaurants and activities we could do.
Her apartment is wonderful. Close to the metro and in walking distance to the city center. If you mainly want to visit the center of Porto, you actually don't need the bus lines or metro at all.
There are shops, bakeries, butchers ans supermarkets nearby and it's not too far to a lot of great restaurants.
So no matter what you want to do in Porto, this is very likely one of the best places to stay.