1. The freezer is NOT controlled by anything. It gets cold regardless of Tstat setting. The tstat controls the lower section.
2. You state you sometimes have to wait a few hours before it will relight on LP. What does the refer do when you try to relight in that 2 hours? Do you get a check light or any code?
3. When you state it shuts OFF, do the controls shut down and no indicater lights are on? Or the controls stay ON but the refer does not cool?
4. Not sure, about your year model control board, but Norcolds have a built in defrost timer that shuts the refer OFF every 48 to 54 hours for about 2 hours to allow the evap coils to defrost the ice build up on the fins. To STOP this defrost cycle, all you do is once a day, turn the refer OFF for 5 seconds and turn it back on and the 48 to 54 hour timer starts all over. I would try this and see if the problem goes away. Doug