People did not travel much, that's why itinerant preachers went from town to town.
Even simple farmers travelled for large celebrations. Also, although many people in villages rarely travelled, news was spread by people who did. And within 20 years of Jesus' death, there were several christian congregations in various cities, all communicating with each other. News had ways of gettin around, even to little villages, and certainly to Jerusalem, where the "head" of the Jesus sect initially was. If Jesus never existed, never travelled around galilee and was never executed in Jerusalem, Josephus and Mark's audience would know this. So would Paul. The early Jews and christians interacted a lot. We know this from later jewish sources as well as roman sources. We know that a mere 30 or so years after Jesus' death, christians were being blamed for Nero's fire. So this sect was well known in the very places where Jesus was said to have preached, gathered crowds, and died. Yet somehow, all the gospels were copied and transmitted better and faster than any other work from antiquity. There is no way to explain this unless people thought it contained truth. Had Jesus never existed, there is no way to explain how so many christian communities preserved such texts while the events described were so recent. Everyone would have known that it never happened.
Perhaps Mark was initially rejected by most people.
Then it wouldn't have survived. More than 90% of everything written in the classical and late hellenistic period perished. Yet the gospels are better attested to (meaning we have more physical ancient texts and more quotations of them in other texts) then ANY OTHER literature from the entire classical and late antique period.
Paul saw God in a vision and that was that, that's what convinced him, he had no facts to check.
He did. He moved around in the same places that Jesus was said to move around. Moreoever, he stayed with peter for days and days learning the tradition.
Followers had to take Paul's word for the fact that he communicated through revelations, visions, and ancient scripture, otherwise no facts necessary.
No, they didn't. There were other eyewitnesses (and later disciples of eyewitnesses) to check with. Even the late first and early 2nd century writer Papias spoke to eyewitnesses and to their disciples. Luke was active among the circles of eyewitnesses. The author of John was a disciple of a disciple of Jesus.
We have no record of a skeptic converting to Christianity in the 1st century
Completely false. Paul was a skeptic, and began (by his own admission, and as recorded in acts) not only as a skeptic but as a persecutor of the church. Acts also records other conversions. Josephus states that Jesus attracted followers.
Skeptics have never been the target audience, only believers in myth and magic need apply.
Again, such "myth and magic" are in all of ancient history. Do you believe that Augustus Caesar was a myth? After all, his biography states that he was born of a god. Obviously, only "believers in myth and magic" would believe that this emperor ever lived.