Rattles

As stated they are a truck and they will ride harshly and rattle especially when they are empty.When loaded with your camping gear and everything else the chassis will be loaded and smooth out the ride and lessen the noise.

In my search for a Class C all I drove were on a Ford Chassis and noise from the engine and rough ride seemed common,then I drove one on a Chevy Chassis and the noise and harshness of the ride was remarkably different.Soother,quieter and easier to drive.

So maybe try to find one on a Chevy Chassis and give it try

I find it quieter if I don't wear my hearing aids.

You didn't say what year and model you were looking at. Things are relative, a cheaper built unit will ride rougher than a Super C on a diesel chassis. The same way a 87 Yugo will ride differently than a 2020 Mercedes. As a general rule however, most gas MH's either A or C will make a good deal of noise going down the road. Some rattles can be chased down and fixed (I was obsessed over this on our previous 2 class A gassers). Some noises would be a greater concern than others, depending on what is causing the noise. LOTS of contributing factors, tires, PSI, alignment, weight distribution, things not stowed properly - a million reasons. You'll need to drive quite a few to determine what's normal and acceptable vs what you can tolerate. If you want the best ride for an RV, look at a diesel pusher.

Only loud rattles I hear are the pots and pans, and the Cast iron pans carried in the oven.

IT'S A TRUCK! Trucks ride rough and shake things loose. If you watch a video of how RV's are built you will wonder how they stay together at all.

One of reason I decided to not purchase a class C. I read many years ago of numerous reports of loud rattling on moving class Cs from many owners and they were unable to solve the issue so I went with a TT and left the noise behind me. Good luck. Cheers