I am looking for the title and writer of a book which has as its central theme a transit point or stopping point for travellers across the universe, the story begins in the early 19th century - maybe earlier - USA I can't remember much of the plot or the author I sued to borrow it from the Library and then moved house forgetting its title - arrrrgh!! Any help would be appreciated, it may be a help or hinderance to know that at one time I thought it was named 'The Postman' but it isn't David Brin's novel. Any help welcome.