re
"Recently I put new, heavy duty
drums on the rear and replaced the shoes>"'

Care to elaborate on that ?
I am not aware of any 'heavy duty' rear brake drums for vanagons.

on the parking brake 'distance the handle will pull up' thing ...
there is some 'free play' built in before the first click...
but .....should have a bit more play there than 'grabs on the first click.'

at least check rear brake temps after 'just driving' .
Might back off the parking brake cable some .