As things turn out, I am studying this exact subject at present. It will be a while before I am done.
However, I can tell you this so far. The commandment is to make disciples, not to go door-to-door. Jesus is the exemplar. The example to follow. He didn't go door-to-door according to the gospel accounts.I think at this stage of my study it is fair to say that the most going door-to-door could be considered is a suggestion. There is no question that one of the best ways to contact people is by knocking on their door and talking to them. Also note that C.T. Russell did not promote the door-to-door approach.
The idea of everyone going door-to-door is a doctrine of the WTS, with marginal support from the scriptures.