We were a group of 5 (2 couples and 1 single) and we stayed at Luciana and Vincenzo place in Ostia for 2 nights after a 2 weeks cruise. It's close to Roma airport that you can reach by taxi for 25-30 Euros. It's a few minutes walk from the train station that will connect you to the subway station to Roma for only 1,5 Euros. It's also close to a big grocery.
As for the Airbnb, it's very nice and clean with 2 bedrooms and 1 bathroom, a large balcony and only 2 blocks from the beach. Thumbs up for that nice place !