I just finished reading a book on the religion of Roman soldiers and there it had also the topic of the afterlife. Romans didn't believe in an afterlife like the Celts and Germanic people that's why they weren't buried with much things. Only the coin for the ferryman Charon and an oil lamp which should light the darkness. They believed in a joyless afterlife as bloodfree shadows in a dark Hades, therefore it wasn't necessary to give the deceased many things he used in this life.
Their grave stones are very stereotyped showing the deceased in his profession, e.g. an auxiliary soldier on horse back riding over his enemy, a centurion in full uniform and stating maybe his data, how old he got and how long he served and in which unit. One fine example is the grave stone for the Centurion Marcus Caelius who fell in the Varus battle. If you go to
www.kalkriese-varusschlacht.de and use the German site (Deutsch) and then click onto "Varusschlacht" you will see a picture of this stone on the left side. Unfortunately this was not linked seperately and is not shown on the English page.
Another comon relief on grave stones is the banquet of the deceased where he lies on a clina being served by a servant.