If you are concerned with carbon monoxide when cooking, just open a window a little bit. At long as your stove is adjusted correctly (no soot on the bottom of your pans) and you are using it for cooking only, not heating the camper, you should be fine. Make sure you have an operating CO detector. http://www.jolietfire.com/pdf/Carbon-Monoxide.pdf
We have a fan in the ceiling centered from side to side in front of the stove. The Range Hood Fan over the stove is a filtered recirculating fan. It's part of the bottom of the Microwave. I run the ceiling fan on low when cooking to help remove any heat from the stove and crack a window slightly if cool weather outside.
Just be sure that you unlock the vent flap on the exterior of the wall just beneath the awning. I have to get on a ladder or stool to reach it. They have little levers so while in transit, the flap doesn't slap around.