Woody,

   Thank you for asking this question. I too have an old moderately rusted
propane tank and was wondering the same thing. I have been running my two burner
stove for the past few days (while home and monitoring it) with a box fan
near the stove to exhaust the heat/spent air. So far I have run them for a total
of 18 hours and still not out of gas, I am not sure how full it was when I
began because like you I am not sure how to determine the current level in the
tank, any way to measure the level?

   I am doing this to drain the tank so I can remove the tank and get it sand
blasted and powder coated along with my two bumpers. I too would like to know
if I should be completely replacing the tank or continue with my plan. Like
you said Woody, Gowesty says replace it, but they are not completely UN-bias in
their opinion. I could never be a sales person, since if you do it long
enough and want to make money you end up selling people things they don't want or
need, and end up lying to do so.

   I do intend on replacing as many of the attached components (valves and
such) as possible.

   Any one got experience with this issue?

Thank you for your time,
Emil
1984 ASI full camper