2019 Northern lite cummins oil change

Up front apology on any format errors I have a basset hound in my lap. All truck campers and class C we have owned have a plate to take off under the camper, then the oil drain plug. there are a total of three vent like covers under the generator and they all have caulk around them. have yet to find which one to take off to find the plug. and the generator seems to run very much on the rich side it is not a L P leak it is a very strong L P smell coming from the exhaust. We were spending the night bringing it home and a full L P tank only lasted about three hours only using the air conditioner. Any help appreciated hope no one gets mad about this post