There is no proof that early Christians went knocking door to door. I would say the chances are slim b/c they were in constant threat of martyrdom. Marytyrdom became so celebrated that it was viewed as your real birth day in Christ. People were so eager to be martyrs they were not prepared and renounced neighbors and friends who were not ready to commit to the step. I assume they used the mass communication of the day. Speaking with individuals and speaking in markets as Paul does in Acts. An early church preparing territory and keeping track of it being worked is preposterous.
Paul certainly travelled and there are legends of the saints travelling far in various directions but these are legends only. Maybe there is some truth in them. The early church had to be rather disorganized. Diversity was certain so I doubt there was any one practice, let alone a rigid cult as to what to do. People followed Paul around to refute his gospel so he was a travel industry in itself.
I believe they would use mass communications today. Christians are still tortured and martyred in most of the world. You Tube, radio spots, cable TV. and speaking to individuals as found in every day life but not trolling for them. When you read accounts, people converted not so much out of rationa belief but by experiencing Christ in the present in their normal lives.
The Society has a very long habit of putting in informative data in the midst of not true analysis. Where others sees perhaps eight strands of thought, they see only one. Others admit error, not the Witnesses. Scripture analysis is hard knowing history and the languages. Reading consecutive verses for long periods is important to understand the whole story. Jesus or Shakespeare said anyone can quote scripture to prove their purpose. The Bible is such a gigantic compilation of books of different genres. I bet I can prove the moon is made of green cheese from scripture alone. It doesn't mean moon rocks don't exist.
This cult authority is what bothers me far more than mistaken scripture analysis. They believe crazy, off-the-wall stuff, but so do other people including myself. The Witnesses have a set up. Ask your own questions, use a real Bible, have a different format than you suggest and you will see just how much knowledge they have. If you are listening for more than a few minutes, the cult magic is already working on you.