Could your CEGUI disappearing problem be the same as this one: [PyCEGUI / CallbackNode render bug with shader generator) ?
Converting a Node to a NodePath is as simple as calling the NodePath constructor:
PT(Camera) myCamera2d = new Camera("myCam2d")
NodePath myCamera2dNode(myCamera2d);Note that a Camera object should always be created as a PT(Camera), never as a concrete object, because it inherits (indirectly) from ReferenceCount.
David