Roman views on the afterlife?

Roman religion was influenced by the greeks so they would have believed that the souls go to the underworld, elysium or tartarus.

While the Epicureans acknowledged the existence of gods, they believed the gods were not concerned with human affairs. No life after death, and nothing to fear from divine retribution.

I think one thing we often overlook, largely because it's gone from most of Christianity, is that the Romans viewed their afterlife as a very active process. As Charles W. King points out on his book on the subject, The Ancient Roman Afterlife: Di Manes, Belief, and the Cult of the Dead, virtually all Romans prior to Christianization were deified, and all of them had the potential to interact with the living, whether it was in the form of receiving offerings or interceding on their behalf -- basically another version of the classical do ut des relationship. Whether that potential was actualized or not was mostly up to the dutifulness of the living in observing the cult of the dead.

Romans viewed death as an eternal sleep, that's why hypnos is both the god of sleep and a deity of the death. What I can say for sure tho is that they saw the dead as polluting and unholy, no armies were supposed to enter Rome without cleaning (purifying) their blood stained weapons, no dead people were to be buried inside the city walls. In some way, they were right, living with the dead is dangerous for the population health wise, but they really viewed it as something impure to be locked outside the city.

Average citizen where and when?

Aristotle views summed up Roman views.

The Romans believed in the Greek underworld, where Charon was waiting for them.