Nina's place is awesome! It's a short walk from the trains and buses, tucked in a quiet alleyway. It is easy to access many main streets in the city and best of all it's a 10 minute walk from La Pedrada and other top restaurants in the area. You will have to walk up 4-5 short flights of steps to get to her unit, so just be prepared for hauling your luggage up (or a stroller).
We paid about 30euro for a taxi from one of the main street to the airport and it was a 20 min ride to the airport (on a Sunday morning).
We traveled with two kids so Nina's place is perfect. The toddler bedroom was very cute and very comfortable for our youngest. She also provided toys and a baby crib which really helped!! (This means we did not have to travel with our pack and play all the way from the US to Barcelona). Thanks Nina!
Check-in was very clear -- Be sure to submit all of your information early because the guide Nina provides is very helpful when planning your stay.
The central location worked out great for us and made our stay much better than expected.