When booking Anna's apartment, there is nothing that is not been taken care of, things that you would not even think of (such as ear plugs, night masks). She has created a web site with a collection of her local tips which is worth a fortune, fell in love with the Sangria place she suggested (a tad too much :)) and the cactus café (what an amazingly great café). The bikes she offers as part of the renting were a neat add ona and we also took the suggested tour, tho not completely (less fit than Anna :)), but it made travelling a lot faster and further than by foot. As almost everywhere in central Barcelona, metro is about 5m away, la ramblas (if you like it) is not much further, beach 20mins walk, magic fountain 20mins walk. I can only highly recommend to book with Anna.
Attention tho, as many have stated before, the apartment is on the 4th floor, so heavy luggage and going up and down often will take some credits of your fitness