What you need:
Power Glove
Acess to the Past

What you do is enter tha Mailmain's house in the past, and then do the following. You walk up to the bookcases on the top-right part of the Mailman's house, and you use the power glove to lift any of them up. Stairs should appear. Go in them. You should appear at the same spot, and on the stairs. Move upwards, and lift up the other part of the bookcase. Beneath it is an already pressed button. Walk past it. You will appear in Rafton's house, but on his wall. You are stuck, and there is no way to escape except for killing yourself with bombs, or turning off the game.