I really enjoyed this airbnb ; I stayed there 2 nights on the week end and it was really practical. Comfy, quiet, clean, there were a few candies and towels put in my room. Carla and Tais are very sweet!
The house is only a 10-15 min bus ride (line 122) from the city center, and the bus stop is right in front of it. There is a bus for every 20-30 min and it goes on on Saturdays and Sundays. However, the bus lines stop working after 11PM so be careful :) the house is a 45-50 min walk from the O connell bridge in the center. The 122 line allows to catch the other buses to the airport.