I also live full-time in my trailer. I'm super careful to not allow noticeable chunks/solids of food stuff to go down the sink drain. Yes, it requires paying more attention, and a little more effort to wipe out dishes and pans with paper towels prior to washing, but it helps prevent the food (organic matter) from decaying and causing odors in the tank AND from settling in the tank where it remains decaying even when you dump. I've not had any problems . . .but I don't know where mine is vented. I use a strainer at times if I have left-over noodle soup or similar so I can pour the liquid down the drain, but capture the solids.
I also purchased a liquid "grey water" tank treatment - mostly because I had some musty odors around the bathroom grey tank. Got mine from Amazon, but ACE hardware, RV supply stores and other places have it as well. Added about 1/4 - /12 cup after last dump and odors are gone. I used it in the kitchen sink drain also just for "grins". Rather than the black tank chunks, there are several LIQUID formulations for use in grey tanks. I'd try treating it with grey tank formulations, (may take more than one time) before closing everything up.
Linda