Jon W., 'Meaning in the Blues' (actually titled 'Blues Fell This Morning') is by Paul Oliver, is still in print, and, like all of Oliver's work, is worth a look. Get a copy via the link to Amazon.com!
To 'ride the blinds' specifically means to ride on the baggage cars nearest to the engine which, having no end door next to the engine, were blind.
'Riding the rods' meant to ride on the iron bars that were located about eighteen inches below the boxcar as braces for the boxcar frame. Some hoboes would carry a piece of board with them to make this slightly more comfortable.
If you want a book that goes into all that hoodoo stuff then take a look at the fascinating 'Africanisms in American Culture' (1990) edited by Joseph E. Holloway.