Using the edges of the brake shoes to grind off the rust is tedious and slow but may work, pulling the drum towards you and rotating and grinding the drum back and forwards and swearing and cursing until your strength has gone and them some more. This worked when I had a stuck adjuster.
copper hammer... that said you might want to fire up the blow torch and penetrating oil to help free off the drum from the hub!!
Stand it up as if fitted to van, then smack the castlenut with a sledgehammer as if teeing off on the eighteenth. That should leave the drum where it is and the rest well end up wherever you're aiming.
