The Simon Scarrow series is about average men in the Roman Legions, during the days of the Empire, that is worthwhile I think. It does need to be read in order. Under the Eagle: A Tale of Military Adventure and Reckless Heroism with the Roman Legions is the first book in the series.
Gillian Bradshaw has several really good books set in Roman Britain: "Island of Ghosts" and "Dark North". She has also written about Roman times in other books, as well as about the era of Justinian and Theodora in "the Bearkeeper's Daughter" The Bearkeeper's Daughter set in Byzantium in about the 4th Century AD. Her books are all "stand-alones". She is an excellent writer, and imo gets the mindset, the "voice" of those times perfectly. One of my favorite HF's ever is her : "Island of Ghosts".Island of Ghosts: A Novel of Roman Britain.
Lindsay Davis, who writes the very popular ancient Roman mystery series w/ lead character/ detective type Marcus Didius Falco (first book in series: The Silver Pigs (Marcus Didius Falco Mysteries) also has a very good, based-on-true-story novel about the Emperor Vespasian and his almost life-long secret love affair w/ an ex-slave woman: The Course of Honor, a Novel.