All they intend to do is supplement power. That is what I do--but on a much smaller scale.
I love my load support and autoformer. The two combined with a battery bank allow me to run my roof air on a single 15 amp circuit.
I deliberately clamp the circuit to 12 amps (1320 watts @ 110 volts), so as not to blow the shore power breaker. Load support, when the air conditioner is on draws up to 520 watts (observed).
I'm currently drawing 1920 watts running the roof air, fridge (335 watts), fan, and laptop. Voltage is 110 so I'm using 17.45 amps. Duty cycle on the roof air is 50%. When the roof air is off, the batteries recharge.
The other option is a campground which is $35 per night. When I am there the autoformer is essential to prevent low voltage from damaging my RV.