Jesus replied, “Let us go somewhere else—to the nearby villages—so I can preach there also. That is why I have come.” So he traveled throughout Galilee, preaching in their synagogues and driving out demons.
Have a look at this map of first century Galilee.
It's rare to see such detail in map of Galilee. Notice how many towns and villages are identified. According to Schnabel, Jesus could have visited every one of them. Not all are identified, but there were a total of 175 towns and villages in Galilee—200,000 people.
Jesus kept moving until everyone in his region had heard the gospel or know someone who had.
(I'd like to hear from you if there's a better quality map of Galilee with the same detail).