<<Remove glove box
disconnect hoses behind radiator so coolant doesn't  go inside van when
disconnecting the core.
Disconnect hoses to core
cut side of housing so that core can slide out.
replace core
glue, epoxy or whatever to re-attach side of housing.>>

This sounds like the way we have found to replace heater cores in Rabbits and
early Jettas.  If you had no A/C there is a door on the box where the heater
core is and you just take the door off and unhook the hoses and slide the
turkey out.  If you had A/C you just cut a hole and then it will still come
out.  We would put the new one in and place the cut out portion of plastic
back over the hole with duct tape (you would have to sit upside down while
driving with your feet to notice it so I have had very few negative comments.)
If VW is replacing rear heater cores for free why not try to get them you
replace your front one for free too?  Couldn't hurt to try.
Ken Wilford
John 3:16