You can always cut the old incoming cord connector off & connect a new 12 volt female receptacle to that end & use a small wattage AC/DC inverter like this one. That will accomplish what you want to do & not have to run the generator or be connected to shore power.
I'm an expert in only one field....I believe it's somewhere in Kansas.
2000 / 22' SKYLINE NOMAD LITE
1998 DODGE DAKOTA / 5.2L= 8mpg.
2006 POLARIS ATV
1500/1200 Watt Champion generator
Yada Wireless Back Up Camera
1998 Dyna Wide Glide
USMC 68-74