The glass on my burb's tailgate seems to be outside of it's left & right vertical channels - how in heck can I get it running back in to them?
Just to complete the story.
I removed the cam channels from the glass sash and disconnected the regulator arms. This allowed me to ease the glass down, open the tailgate (finally!), clean & lube everything, set the glass correctly in its side channels and reconnect the regulator arms to the cam channels.
I now have a working tailgate window - just need to fix the external keyswitch.
GOOD GUY ALERT: Thanks to Caddylow for the help and advice.