I had stumbled upon this thread once or twice before....
There is 100%, absolutely, positively, NOTHING wrong with knocking on doors...
I love the guys that immediately post things like "Well, of course people will hate you, they don't want to be bothered!"
Well, guess what? For every 4 people that slam the door on me, 4 people will talk to me. And even if I am not making a sale, I am introducing myself and telling folks a little about my business.
I have done some limited door to door marketing in neighborhoods that I was trying to infiltrate and it has worked out great.