By Ringeltree
 

Also if you use control-drag you can move walls a bit down into the ground so they don't look like they are floating.

By Ringeltree
 

One trick you might want to know about. If you make the teleport exit visible, you can turn it the direction you want, then make it invisible again. That way characters face the right way exiting doors.

By Ringeltree
 

I saw your post on the forums. That was pretty fun!