Each campground is unique, and company policies vary. The campgrounds I hosted at either had running water or the company would fill a 50-gallon drum on stilts when needed. I was never very remote, small stores were always within 5 miles. I did take 30-50 mile each-way trips to go shopping almost every week. There are campgrounds 100 miles from the nearest store or fifty miles of bad 4wd road. (Latter is white-water rafted to.) Generally you will have two days off each week, and will need to be able to store a weeks worth of food.