A brief museum review that might be of interest:
PhoneCo [Galesville, Wisconsin] is a museum which grew out of some guy's weird hobby, in this case hunting and capturing telephones. It is a working business -- for example, they supply film and television sets with historically correct telephones. They also do repairs and house an impressive array of telephones and related equipment. The 'museum' is crammed into hallways, spare rooms, the PhoneCo business office, and the shipping room. It is grubby and poorly lit, so I may or may not have seen cockroaches. There is no admission fee, and visitors are welcome to wander about at will, the lines between business and museum happily blurred.