My house is wired with a transfer switch and a 120v, 15a male plug. During power outages I run my nearly my whole house off of my camper's Onan generator. It works just fine.
I can't plug into the camper's outside outlet since it is GFCI protected. The neutral and ground are connected at my house as required by code so this trips the GFCI. I plug into the microwave outlet; it's not GFCI and it's 20 amp instead of 15.
Your cabin should have a ground rod or two driven into the dirt. These should be connected to the ground wire of the cabin's internal 120v wiring. If it were served by utility power the neutral would also be hooked to the ground system at the service panel. If you want to feed it from an outside RV outlet you will have to leave the cabin's neutral unbonded.
