We went camping without water or electricity hook ups for 4 nights with our 8 kids (18,16,14,13,10,7,3,1). We had originally planned to just hit the battery disconnect for the trip and turn off the propane at night for safety reasons. We would use the toilet at night and the vault toilets at the campground during the day. We would use flashlights and a battery operated LED lantern for lights and our 5 day cooler for food.
We had been using the fridge on the first leg of our trip so when we got there, the fridge was still cold. Our 5 day cooler did not seem to be keeping our food as cool as we wanted so we decided to use the fridge. DH said if the battery died, and it was not good after, we would just replace it. He wanted to "experiment." And we didn't want to have to be constantly checking/worrying about the food going bad and adding ice.
We ended up using the furnace 2 nights. Unseasonably cold in the low 40's and we were worried about our 1 and 3 year old being warm enough. Other two nights were low 50's and we were good without the furnace.
My husband had put some water in the fresh water tank....just in case.
So we used the water pump and the hot water heater one night to clean the little girls off at night but decided it was just as good to heat up water on the burner and fill the shower with a couple inches of water and just let them splash a little. I also took a navy shower one night because I was just covered in dirt and it was too cold to go in Lake Michigan to "wash" up, the water felt like ice! yikes! We did turn on the pump a few times just because it was easier than trekking to get water from the spigot but for the most part we had water in the bathroom to wash hands and to flush.
I did use the fan/vent on the stove a couple times when cooking inside on the burners.
As the battery was getting lower, we plugged in to the car and started it up for about 2 hours. It helped a little.
We never used any lights because we do not have LED.
The battery died on the morning we were packing up to leave. We plugged into the car to bring in the slide and the awning.
Our black tank was showing 1/3 full, gray tank 2/3. There was no dump station so we had to drive home with it. We filled both tanks with water at home and dumped at the storage facility we use for the trailer.
It worked out well....but if we did this type of camping regularly, we would definitely buy a generator and have not ruled that out when we have a little more money in the budget.