In N T (Tom) Wright's Paul for Everyone - Romans Part 1, he aptly describes the type of people his audience would consist of. I think this provides useful information for us to understand Paul's letter to the Romans, and what the gospel (literally means "good news") means for Paul's audience.
"In ancient Rome as today, of course, the rich people lived up in the hills, the famous seven hills on which the city stands. The original imperial palace, where the Emperor Augustus lived at the time when Jesus was born, occupies most of one of them. Nero was emperor when Paul was writing this letter; his spectacular palace is on another hill, the other side of the Forum. But then as now the poorer people lived in the areas around the river; not least, in the area just across the river from the main city centre. And that is where most of the first Roman Christians lived. The chances are that the first time this great letter was read aloud it was in a crowded room in someone's house in the low-lying poorer district, just across the river from the seat of power." (page 6; emphasis added)