Clauses and Phrases

Just wondering how correct the following analysis is, of a rather long sentence, I came across on a book cover.
“Amid the chaos of 1970's counter-culture, he retreats to his ancestral home of Grass Valley, California, to write the biography of his grandmother: an elegant and headstrong artist and pioneer who, together with her engineer husband, made her own journey through the hardscrabble West nearly a hundred years before.”
Amid the chaos of 1970's counter-culture,= Prepositional phrase of time
he retreats to his ancestral home = Main clause
of Grass Valley, California, = Adjectival phrase
to write = Verbal phrase
the biography = Noun phrase
of his grandmother:= Adjectival phrase
an elegant =Adjectival phrase
an elegant and headstrong artist = Adjectival phrase
an elegant and headstrong artist and pioneer =Adjectival phrase
an elegant and headstrong artist and pioneer who, together with her engineer husband, =Adjectival phrase
made =Verb
her own journey =Noun phrase
through the hardscrabble West =Adjectival phrase
nearly a hundred years before. = Prepositional phrase of time
Thanks