OI too will go with Second opinion.. But in the meantime.....
Pick up a portable.. like a Honda or Yahama (or other) Inverter generator.
Most over 3500 watts will be dual voltage 120/240 and have a 30 amp twist lock (or larger if bigger) Get a matching "Pigtail" (Cord) long enough to wire it into your RV's generator in junction box.... Now... Make sure of two things.
ONE Generator exhaust points AWAY from RV
Two. Genertor is secured to discourage it growing legs and walking off.
It may be possible to "mount" it in the RV's generator compartment. At least Temp mount.