How to calculate "duty" when between flights in a 135 operation
I have not checked the latest regs, but the time beginning at the point where the pilot is done with all postflight duties until the time the preflight duties begin (ex. checking weather) is considered rest time ONLY IF the pilot is really off the clock.  If the company requires anything of the pilot (ex. "stay near the plane...just in case"), it is not rest time.