A few years ago we had problems with Stink Bugs, that is more horrible than the beetles. But I found a solution that worked pretty well, and ever since, we've not had any kind of infestations like that since
I picked up a 4 pack of those Raid Bug Bombs from Dollar General. I made sure everything in the camper was put up (like food and dishes) and then set 3 of them inside the camper and the forth in the underbelly behind the pass through wall. I set them all 4 off and stayed out of the camper for about 2 hours. We wiped down the counters, changed the bed linens, and swept up the dead bugs. And then an hour later, we swept again. And an hour after that we swept again, and then the next day we swept again. They were all dead and we did not see any living ones crawl around.
They were dying as fast as they came in through the cracks and wherever they came in. Oh, I also turned on the air conditioner fan when I did this so the bug bomb would reach inside the air ducks in the ceiling and if there were any leaks in the air ducts, it would also send the spray into the cavity of the attic.
I waited 10 days and then repeated again. I waited 10 days and repeated a third time. We never found live one's again. We only found an occasional dead one after that.
The next year, I repeated again. And once a year I repeat now. Then end result is.... wherever they were coming in is now treated with the bug killer and they have to pass through it, which kills them.
It's now been over 3 years and at most, we'll find a new dead stink bug, an occasional dead spider, and sometimes, a dead ant. We've never had beetles inside the camper, although sometimes, we have had the camper covered with lady bugs. They don't come inside.
It's a very simple solution, but when you set off the bug bombs, make sure your air conditioner fan is running to help circulate the bug bomb chemical into areas a spray aerosol will never reach.
2019 Montana High Country 375FL
2014 Chevy Silverado Duramax, 6.6L Dually