Keep in mind that to be self contained, in boon docking mode, the main power system will be
12v. Only the outlets, AC, microwave are 110v. You must be plugged in to shore power or use a generator for them to function.
Lights, water pump, furnace fan, all
12v. Frig runs on propane but also needs
12v to operate it's control board. An inverter would let you watch TV. Some of the new trailers may have a built in inverter.
How long the batts last depends on how much 12v you use. Lights are minimal, furnace fan uses lots.
John