Every time we tow our hybrid when we get to the site or get home we had a bad sewer odor in the camper. Just open windows and turn on the fan and its gone in a few minutes. I've tried towing with the ...
Depending on the road, bumps, turns, etc, I often lose water out of one of the sink or shower drain traps. It does't take much sloshing to remove enough water to allow odor inside. A quick refill and run the fan a couple minutes and all is good.