I will be taking my '91 22 ft fun-chaser on a shakedown run in the high country for a few days. It will be warm in the daytime (mid 60s maybe) but cooler at night (20s or so), ya, it is still winter here. This will be my first outing with a self contained camper. With 2 batteries and a generator I will be running the heater around 50 degrees or so at night. Under these conditions can I use the water system in the camper or should I just carry a couple 5 gal jugs for the necessities?