Writer Leslie Bennetts must have felt plumb tuckered out after researching, assembling, and writing Last Girl Before Freeway: The Life, Loves, Losses, and Liberation of Joan Rivers (Little, Brown). Doing a biography of Rivers meant tracking a tornado for decades as it zigzagged across the country and back, a tireless whirlwind of creative destruction that spun sacred cows airborne and cleared a path for Kathy Griffin, Sarah Silverman, Lisa Lampanelli, and other oral assassins. Greenwich Village nightclubs, the Broadway stage, television, movies, the best-seller list, the home-shopping networks, the Manhattan social hierarchy: Rivers tried to conquer them all and mostly did, rebounding from failures and blood feuds that would have flattened most entertainers. Born in 1933, Rivers was a wisecracking wraith powered by a craving for acclaim, love, money, and…