I spent two weeks at José's airB&B in January 2017. The place (Vallvidrera Superior) is perfect if you like to be in a calm area but still close to Barcelona city (count 30min to the city center taking the funicular+ferrocarril as public transportation). Once you get off the funicular that takes you from Peu del Funicular to Vallvidrera superior, you land in a "bubble" that offers a huge contrast with the crowded city. You'll also have a beautiful view over whole Barcelona
and some nice places to go hiking if that's something you're into.
José has proven to be very helpful and is committed to make your stay a success!