You go out the sink and there is a secret entrance into the bottom of the fridge somewhere outside. You will be in a basement type thing, follow the stairs into the fridge.
You can also get into the freezer and the lazy susan.
I'm telling anyone how though. :D
Oh, and there is a secret glitch room you can only get to by admin camera. There isn't anything in it, and you can't actually build in it. Its completely black.