Make sure you check out the RV wiring before relying on the electric heaters. RV outlets often use a sort of insulation piercing connection to the wire, unlike household outlets, and are usually not superior quality to begin with. These connections can get poorer with age and a poor connection with a heavy current draw can heat up considerably. It might not be a bad idea to replace the outlet(s) you plug the heater(s) into with good quality spec grade outlets (in the needed electrical boxes) if you can manage that.
Also be aware that many electric heaters, especially cheap ones, have barely sufficiently sized cords; avoid bunching up the cord or having it nestled in upholstery or under a rug.
I keep a small heater fan in my motorhome. I've mainly used it to take the chill off of cool mornings and to exercise the generator in the winter. The fan only mode is also occasionally handy, though it's certainly not a powerful fan by any stretch of the imagination. I am quite cautious about running my heater unattended, especially on high, for the reasons outlined above.