We normally boondock (not to be confused with dry-camping in a Forest Service campground), so there is no source of water nearby. Fortunately, we have a 40-gal tank, so we have more available to begin with. But,
I also fill the water heater while I am filling my fresh tank, and put some water in the cassette toilet to dissolve the chemical on the way, and have the initial toilet "charge". This way, I am not using some of my limited-supply of fresh water to fill the water heater and charge the toilet when we get to camp.
But, I also carry a full
6-gal jug (get the spout shown, as it goes into the fill neck perfectly). This gives me 52 gallons when we start camping. DW and I can go 8 days and 8 nights with our water, taking a Navy shower each, every-other day. Usually don't need the extra 6 gallon jug. We don't take bottled water for drinking, just use the on-board water.
We also have 200w of solar, so we don't need a genny, or the gas to keep it running. Two 110 Ah batteries (LED lights), and we are good to be remote the entire time.
Have fun, and enjoy the remote wilds! If you are dry camping in or near FS campgrounds, water is not as much of a problem, if the campground has water - many don't.