I have only ever once seen members of the Seventh Day Adventist church actually engaged in a door-knocking activity. This was over 40 years ago, and - specifically - they were soliciting funds for their "missionary works".
As an aside, there is at least one country in which the SDA has a significant presence, and that is Papua New Guinea. This is a country which is proud to describe itself as being "Christian"(rather hard to believe at times, but there you go!) Most of its population of just over 10 million people is divided about evenly between the Catholic, Anglican, United, Lutheran and Seventh Day Adventist churches - each with a membership of about 2 million people.
At least in PNG, the Seventh Day Adventists are on an equal footing with the more "mainstream" churches.