1-electricity~A 1000 watt gen for just lights and battery charging. 2000 watts of using a microwave and 3000 watts for air conditioner.
2-sewer~Porta-potti and a screen over your hose from the sink drain although I have never had issues without a screen just using a garden hose for the drain.
3-Water~I have several 25 and 50 gallon water barrels and can tell you gravity feed works okay for filling the water tank but not for any kind of pressure through the lines but if you connect a RV water pump between the water container and the trailer, you get great pressure.
4- Hot water~If I don't have a water heater I always boil. It makes bad water good and poured over the dishes it sterilizes, infact Boondocking, I always boil and rarely use the hot water heater because we use creek water for most chores.
Enjoy. Boondocking is the only way to camp!