There is a way to be completely safe inside an RV while it's built-in, or an outside portable, generator is running: Pressurize the interior so no fumes can enter. I turn on the reversible roof fan with it set to push air in. This keeps a slight but very important amount of air pressure inside the coach.
Hence, so no generator fumes can enter. No "real breeze" is felt if all other coach openings are left closed (so this method can be used in cold weather, too). The fan is "trying to" bring air in but can't if everything is closed up. However, the internal coach air is raised just enough in pressure over the outside air pressure so as to block any outside fumes from entering.
This works great for us ... and is good way to also keep road dust from entering the interior when traveling on gravel or dirt roads.
