Peder,
Some basic facts about = LP-Gas:
4.24 pounds per gallon of lp gas.
91,502 BTU per gallon of lp = gas.
21,548 BTU per pound of lp gas.
Vapor pressure at 70 deg F 127
Vapor = pressure at 110 deg F 230
=
The westy lp tank has a capacity of about 3 gallons.
But there = should always be at least 20% vapor space in the tank.
Last time ours = was completely empty, it took about 2.75 gallons,
if memory serves = correct.
So the tank should hold around 11.6 pounds of lp gas.

The westy frig runs on lp gas long enough = that
you lose track of when you last filled up the lp tank.
For us, the 3 = gallon tank usually lasts one week
cooking 3 times a day, and using the frig on = half setting.
We never use the frig only. So we can't give you an exact figure.
Also it depends on how hot it is. The frig probably uses = more
lp gas if it's warmer outside, to keep cooling.
We usually turn our frig = on 12 volt when driving.
Reason: The vanagon has to parked level to use the = frig.
It's easy to damage the frig if you park someplace at a angle,
and you left the frig running on lp.
The 12 volt setting = turns the frig off when the engine is turned off.
So no chance of damage to the = frig.
We only use the 110 setting at home to precool the frig.
Harald