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 ...
Get some rubber sink stoppers and plug sink & shower drains. You could be losing the water in drain 'P' traps and grey tank odors are coming up thru drains.
Waste tank odors come into rig thru when something is not working correctly: Empty 'P' traps Air Admittance Valves (under sinks) Toilet bowl seal Toilet floor flange Broken/cracked drain/vent lines and/or fittings