Heater in my camper.

A properly maintained FURNACE that uses a heat exchanger is by far the SAFEST means of heating an RV. These furnaces bur air from outside the RV and separate combustion from the inside air. Electric space heaters are safe to the extend that they are properly used but MOST can start a fire if combustible material comes into contact with them (towel falling from a bar, or carelessly placed clothing or blankets). Other electric heaters that do not get hot enough to start a fire are STILL subject to electrical problems such as shorts etc. so can still be a fire hazard under some circumstances. Fueled space heaters are the LEAST safe of the options for heating as they present both the direct fire hazard of setting combustibles ablaze AND they are also a possible CO hazard. In addition to these normal hazards, they burn air from inside the RV and that is what the occupants are breathing, making them a hazard for asphyxiation due to oxygen deprivation. I'd get the furnace inspected and use that as the heat source. It's economical, usually spreads heat from one end of the RV to the other and is the safest way of heating.
Good luck / Skip