You can go a fair amount of time on a larger black tank. Couple mile haul every few weeks to dump black sounds easy.
Or if it were me, on 20 ac in the middle of the woods, I’d make a small buried “septic “ out behind the camper to dump the black tank. Who cares? That’s what outhouses and septic systems doo. Some city slickers on here that don’t understand that food isn’t born in a grocery store and poo goes back in the ground will freak out though.
Gray can get dispersed into the woods.
Hauling water in is a pain, I’d think about that and have a decent tank in your pickup that you can bring in larger quantities. No reason tap water or well water from up the road can’t be drinking water.