Karl,,,,best bit of advice I give you is jack the rear end of the van off the floor 10-12 inches and you will find you will loose only a minimal amount of coolant from the system.
Also you may find the hose clip on the large hose is right behind the rear engine mount and a bit of a sod to get at, unless some kind soul has re positioned it in a previous life.
Regards
Fritz,,,,,,
PS, Don't forget to lower the vehicle before re filling the water system.
One day you will find me,,
Driving in my Camper,
With a Surf and Paisley wrap on both sides....