Boondocking is a great option if you want to be spontaneous. Your gray water should be your limiting factor, and for that it’s learning tips for managing it. You can also manage your fresh water better. Both may be inconvenient but the benefits far outweigh the negatives as far as I’m concerned.
Tips for fresh water:
1. Get a Berkey water filter. They are pricey but then you can use lake or river water!
2. Carry a jerry can of water or 2 and use that instead of relying solely on your tank.
3. They also make long flat water bladders they let along a bed of a truck or something like that. I’ve seen them at camping world.
Tips for gray water:
1. Do your dishes outside. Or if you do your dishes inside, use tubs in the sink and dump the tubs outside.
2. Only take showers once a week and use alternate methods for hygiene. Check out No Rinse body shampoo and No Rinse shampoo. There is also a product called Scrubbz which works for body and hair. Wipes also work, of course. Amazon carries all these things. Or bathe in bodies of water where you are camping — use eco friendly soap if so.
3. When you wash your hands, have a plug in the sink drain. Then use that water to wash your hands next time and rinse quickly with fresh water. Or use anti-bacterial gel for hand washing.
Tips for black water:
1. If there is a drop toilet or other public toilet, use that as much as possible.
2. Invest in a composting toilet. You can buy one on Amazon for around $900.