I also wouldn't mind pulling the pork once done and reheating the pulled pork somehow. I've heard of putting in plastic bags and then popping those into boiling water. Thoughts?
just a little quick research.... follow up with your own though.
I have reheated food in a zip lock bag in a microwave and its ok health wise... ( according to SC Johnson..the mfg of zip lock)
I have little concern of degradation of polyethylene at lower temperatures as millions of miles of it have been installed for radiant heating systems and domestic (nsf approved) hot water piping in this country over the last 20 years and it is not showing any signs of heat fatigue from the temps associated with these applications which are up to the boiling point. It will become softer and more pliable so maybe support it when removing it from what ever you decide to reheat it in.
I would use caution when reheating to make sure there is ample water around the bag and it is not in contact with the bottom of the container. remember that you only need your water temp to be slightly hotter than what you want your finished temp to be, you arent going to be eating 210 degree pork so no reason to reheat in boiling water. I also wouldnt over stuff the bags as it will take for ever to transfer that heat to the middle.
Not sure what kind of camping you are doing and what you will have available, microwave, gas cook top, camp fire, charcoal grill, lost of options for reheating, most anything you can come up with will turn out fine with swine.
or just put a touch of apple cider in a pan for moisture, lid it, and then reheat it in a pan... pork butt is hard to make inedible IMO.