Test Drove 2 DP's this weekend... and an earthquake...lol

If it's cabinet rattles, those can be traced down and addressed by realigning doors and latches to fit better, adding foam or sound dampening material.

Chassis rattles are tougher...new shocks, springs from Deaver Springs and going through the underneath to make sure everything is tight and nothing is hitting the frame or other components when you hit rough patches. Common rattle maker is plumbing or exhaust system.

An alternative is a 5th wheel, most trucks now days are as quiet and comfortable as a Cadillac.