We don't wash plates or cups or bowls when RV'ing - boondocking or not.
We use disposable paper versions of all three ... cuz trash repositories out in the middle of American nowhere are easier to find than potable water is ... to be used merely for washing stuff off. If push comes to shove boondocking I can cram many days of paper debris in a plastic bag and then cram the bag into our largest outside storage bay until we can dispose of the plastic bag when we return to civilization ... or even just burn the paper stuff if there's no civilization.
The five things I hate most about RV'ing is filling fresh water/propane/fuel tanks and dumping black/grey tanks. I wish I had a dream RV that was only 22 feet long, 8 feet wide, 10 feet tall, self propelled (no towing), and could carry enough provisions so as to leave home fully loaded, travel thousands of miles, and then return 2-4 weeks later without having to resupply or dump anything, including food.
Except for length and height, maybe Earthroamer's largest model comes close to making this possible.
