Mark 16:15 is not part of the Bible it is an addition to the Bible actually from verse 9-20 they are not true verses of the Bible you can get that from the Internet
Mark 16:15 is known BT scholar as the longer ending of Mark.This ending is quoted by a bishop lrenaeus around the year 180,so we do that the document was in circulation during the second century, However the eleven verses do not appear in many important manuscripts including the two oldest surviving greek manuscripts of the new testament the codex sinaticus and the codex venticanus
I personally went to the British library I have seen it with my eyes I even bought photocopy of those texts it is in the 4th century it does not contain Mark 16:15 the verse is not confirmaty with Matthew 28:19 it not true to be going from house to house you can preach tje Gospel of our Lord Jesus Christ through the Internet.
We can preach the Gospel through television,radio,MP,satellite
Acts 26:26 For the king knoweth of these things, before whom also I speak freely: for I am persuaded that none of these things are hidden from him; for this thing was not done in a corner.
Apostle paul did not preach the Gospel in a corner he preach the Gospel in the temple
[source bible reader] http://play.google.com/store/apps/details?id=bible.kingjamesbiblelite