I like your style,

Keep it simple and functional. I think I am going to do it exactly as you say except I think to control the device I will include a iButton eeprom with a code on it which will come with the installation and another with another code telling the pic to just keep output on.
Have you any code on reading and writing to iButton EEPROM? else I will just plough through the datasheet and work it out the long way.

Thanks & best regards

Chris