TRAVELS: NEAR AND FAR OUT by Anthony Carson. 309 pages. Pantheon. $4.95.
PASSWORDS by Alastair Reid. 238 pages. Little, Brown. $5.
What is a young man to do today if he has a genuine urge to become a bum? The modern world is tougher on the vagrant than all previous civilizations. Hitler herded Europe's gypsies into Dachau and Buchenwald along with the Jews; the Soviets liquidated the bez-prizornye; the Welfare State frowns on the free-roving tramp; the American hobo has nearly died out, and even the Australian swagman, so mournfully celebrated in the national song,...