I just completed a little experiment.
On Friday Sept. 3rd I lit the propane
on the refer in my 16 ' Scamp
I left on a trip a trip the following Monday.
On Tuesday morning, the 7th, I lit the hot water heater set the temp at warm and left it on for the entire trip.
I spent time in Zion, Teton and Yellowstone NPs so I used the furnace
almost every night. The furnace
was set on the lowest setting but it kept me warm every night.
I have dual tanks but the second tank has been turned off the entire trip.
I got home yesterday afternoon. This morning I turned off the propane
and still had hot water and a cold refer.
My standard size tank has lasted at least 2 weeks with above normal usage.
I hope this helps others that have been wondering how long their tank will last.