and put in an oil drum and gone; the only way he made it to Jersey would be in an oil drum for some dumb reason
That's exactly how I think it could have happened. A lot of garbage including chemical waste was being shipped to New Jersey at the time. If they put it in the sealed trailer especially one marked hazardous waste or chemicals no one would have thought to even check inside it. New Jersey's about a 9 and 1/2 hour drive from where Hoffa disappeared but if they put it on a truck in the truck went straight there ,
he could have been buried before anybody really knew what was going on.