I had a friend describe his first experience in an RV (albeit a rental unit).
"It's like driving around in the silverware drawer."
Funny, because it's true!
Some of our more "significant" annoying noises (not all "rattles") were these:
- Screen Door; we discovered it was primarily the metal kick panel in the bottom most section of the door that was creating the racket. Ran a lap of black Gorilla tape around the perimeter 6 years ago when I got home from the dealership. You can't even see it, and no more rattle.
-Microwave tray; we cut a pool noodle to size and wedged it between the tray and the roof of the microwave.
-Water heater foam; I reached down in there and pushed the styrofoam back slightly from the fittings so it doesn't squeak quite so much
-Silverware; we use primarily stuff with plastic handles, so that seems to help as does having shelf-liner in the bottom of the drawer and an "organizer", which keeps them a little more separate so it's not a bucket of rattling
That's pretty much it. We got enough of the rattles out at the beginning (all the ones we could do anything about anyway, can't do a lot about the road noise) that if a new one shows up, it's relatively easy to locate and troubleshoot.
I have one above my head behind the trim piece that covers the cabover joint. I'm sure it's a loose screw or 3, but I haven't gone after that one yet.
I also laid down self-adhesive sound deadening/heat reflecting material under the vinyl mat in the cab and insulated the doghouse. Those made a little difference, but it's still SUPER loud in the cab when at highway speeds. I intend to eventually remove the door panels and insulated the doors, and remove the bunk ceiling and insulate up there, and remove the wing panels and insulate back there, But there's only so much time and money...