We usually go boondocking a couple times a year for 10 days straight with our camper. It's got a 120 gallon fresh water tank and usually lasts the entire time. I don't think we've run this trailer low on water yet, if we ever did we're usually near the headwaters of a bunch of rivers so as long as we have jugs were fine. If the pooh tanks gets full I have a little turd tank on wheels in super duper emergency situations. Otherwise dumping the pooh tank is pretty easy. I like the idea of the not having to deal with rv dump stations. My shat doesn't stink but I don't want to have to smell or see anyone else's though.
As for heat and hot water goes, we have the typical propane water heater and rv furnace(and fridge) but I'm wanting to install a couple diesel heaters. The biggest power draw is the furnace motor. And the heat distribution sucks. I believe they have diesel fired water heaters, and I think they have air heater/water heater combo units too.
Recently the all in one diesel heaters have been as cheap as $75 on the jungle site, I don't know how legit the seller of them was/is though.
Maybe the ideal setup would be one or two of those electric minisplit/heatpump units? Fill the roof with solar panels and have a good sized battery bank. Ideally shouldn't need to run a generator or get propane/diesel. Power a fridge off the magic solar too.
I'm always trying to figure out the perfect setup. I'd like a woodstove in the trailer but have nowhere to put one.