The apartment was very clean and newly renovated it seems. Alessia was very polite and we could do the check-in earlier. And she explained to us how to get to the port and what else to discover in Naples, which was very helpful. The bus station is very close. During the day the bus regularly goes to the Garibaldi station where you can go to Pompeji, Vesuv, Sorrento etc. by train or you can take the metro to the port to visit Capri, Ischia etc.
If you want to take the bus back at night please consider that the last bus leaves from Garibaldi at midnight. But from there you can walk back to the apartment, which takes you about 30 minutes. So everything is quite close.