Maria has a very sweet apartment in a quiet building in San Telmo, convenient to the Subte and many very good restaurants (and ice cream! Do go to Nonna Bianco!) She had an internet problem when I arrived and went above and beyond to try to get it fixed, even arranging for me to piggyback on her neighbour's wifi when the internet carrier was slow to arrive.
We only spoke by phone and texted, but she has a very reliable person who was waiting with the keys and made check-in and check-out very easy.