I camp as the op does alot whether it be snowmobiling/hunting or Stealhead fishing.Depending on the camper I have at the time,we use porta-potties/bottled water and a catalytic heater to stay warm.
My Lance is winterized right now but ready to be camped in.I have not measured the bathroom for a porta-potti yet(probably to cramped to use) so we would use the toilet with rv antifreeze and or rock salt,which works also.As for showers as mentioned above,there are lots of ways to clean up in the shower space provided without onboard water.We usually use creek water for that.
We rarely stay at an RV park either..99.9% boondocking in the mountains of Idaho where we live and play.