My trailer has been bug free since I got it 4 years ago. I have been through every inch of it and not even a mouse dropping.
Last week we came home at dusk and when we drove into our driveway my truck was covered in gnats. We could see them swarming all over the place, like the plague.
They even got through our closed windows in our house and past our screens.
Anyway, I forgot all about the trailer. I always leave a vent open for ventilation. When I went into it a few days later, I found dead gnats all over the place. There were about 100 in the screen of the roof vent. I pulled it down and found another couple of hundrend in the metal screen frame. They kept falling on the dinette table below. Yuck!
I had to get them cleaned out because we were leaving a couple of days later.
Well, we went camping and we would find about 10 dead gnats on the floor all the time. As soon as we cleaned them, there would be more. We found them in the beds, in the fridge, in the bathroom, everywhere

I decided to pull the entire A/C cover off and found about 100 dead and alive ones still crawling around. They were getting airborne with the a/c and landing all over the place.
After the cleaning it reduced them somewhat but thery are still there. I need to get these cleaned out before the next trip. I'm sure they came in through the roof a/c and I will need to get up on the roof and pull off the external cover off and clean it as well.
I'm and thinking of using a fogger in the trailer to kill any live ones and then start the deep cleaning.
What do you think of using a bug fogger in such a small area?