By sea, it would only take about seven days to travel from the Roson Empire to the Arkas Empire. Once they reached the Arkas Empire, it would take about three days to reach the port city of pudding, which was the closest to the Duchy of Versailles. When they arrived, Ryan and the others would have to get off the ship and change to a carriage. After about seven days on land, they would reach Casar city.
As for the three-in-charge generation that Hart mentioned, they would encounter it on the fifth Day of the Sea journey. It would take a total of two days to sail, and these two days of sea journey were the so-called three-in-charge generation.