RE: Residual pressure in propane line
Mike, did you bleed off the residual propane in the lines (like to the
stove) AFTER closing the main valve and THEN find rsidual pressure again in
the morning?  If not bled off the night before that would indicate that the
interior lines are secure, they held pressure overnight.  If the lines were
bled, stove valve then shut offm and pressure found in the lines again in
the morning I'd be checking the main shutoff valve since it had pressurized
the internal lines again overnight.