Leslie Adkins & Roy A. Adkins, “Handbook to Life in Ancient Rome”

A couple of notes:  (1) There was no consensus among Romans about an afterlife.  (2) “Most early Roman gods were not anthropomorphic in nature until they became identified with Greek gods, so there is unlikely to have been much scope to invent myths about Roman gods.  There is very little surviving evidence for Roman and Italian myths before the Romans adopted many of the Greek myths.”   (275, under “Myths”).