Never take rides from strangers, counsel the wise elders. By this time, though, author Elizabeth Gilbert is no stranger, but a friend eager to take readers along on one joyous ride after another — fiction, memoirs, whatever moves her. City of Girls, Gilbert's latest novel, has the faint whiff of the expected, beginning with the almost obligatory use of the word "girls" in a title, a trend that shows no sign of abating. What's next? The Girlish Girls of a Girl's Girlhood?