Gabriel and his friend were very friendly, they speak good English and gave me excellent guidelines like to visit Stiges - an old and beautiful town 45 minutes from Barcelona by train.
Gabriel's flat is spacious and located 1 minute walk from Saint Marti metro station(L2 line), which is four stations away from Sagrada Familia.
You can change at Passeig de Gracia metro station to L4 yellow line to go to different beaches, otherwise walking from his flat straight till Llevant beach is around 25 minutes.
Highly recommended!