Ghostman by Roger Hobbs Alfred A. Knopf, $24.95, 321 pages, ISBN 978-0-307-95996-6 Who among us hasn’t dreamed, at one time or another, of chucking it all; going off the grid and living a life of anonymity?  No name, no taxes and no responsibilities . . . answerable only to oneself and the whims of chance.  Soon however, like running off to join the circus, or driving a Corvette from