Connect a D/C to A/C power converter to the generator. Plug the positive wire from the converter into the positive terminal on the generator. Plug the negative (ground) wire from the converter into the negative terminal on the generator.
Plug a surge protector into the converter. The surge protector should match the power output of the generator. For example, if the generator is 1,000 watts then the surge protector should also have a shut off at 1,000 watts. This will prevent the power consumption in the cabin from damaging the generator.
Plug a high voltage power bar into the surge protector.
Plug extension cords into the power bar and run the extension cords into the cabin and position them where you would like outlets.
Turn on the generator and test the system.