There are many of these guest ready places which offer affordable stays in Porto(Oporto) . I stayed in the old town by the river, This apartment was spacious, it appeared newly renovated, and walking distance to many sites and entertainment.
It is what used to be the workers quarters, lots of fishermen homes, skilled laborers, and tradesmen of the city used to live in the area. There are very steep hills and inclines, so it is not really ADA. But there are plenty of hotels that can offer those amenities.
I thought I was choosing a apartment with a view or daylight, It has windows but they are very close to the next building. The shower drained slowly, which was a nuisance , but everything else was really nice.
Oporto is going through growth and renovation and has room to grow and in need of investment, but the bones of the city the heart is beautiful and intriguing. I would suggest doing the tours, hop on hop off bus, all the markets, and the food. It is full of seafood. Great!!! There are several hidden gems around the place i nthe hills, you just have to look and maybe lucking happen upon them.