I have just been on a 2 1/2 week camping vacation.
I had the fridge running on propane continuously.  
We used the stove for 1 evening meal as it was storming outside but we
usually use a coleman on a picnic table.   The fridge is basically the only
gas consumer.
The fridge ran for 14 days then quit for lack of gas.
I got it filled up at a RV place in Estes Park.  It took 2.7 galls and this
fellow had lots of experience of VW campers.    My auto fill valve died so I
use a straight filler and get them to open the safety valve a bit and watch
for liquid.

This probably jives with experience of others but I thought I would share it.

Steve Cotsford
'84 Westy