Welcome aboard! Hope you have GREAT fun on your travels. When we bought our rig we had 2 different rattles coming from the door. The first was the metal panel in the bottom of the screen door was loose in it's frame. I just used some caulk to dress the joint and that was solved. The 2nd was a metal-on-metal noise from the door latch vibrating against the latch shaft while in motion. I just wrapped a piece of gray tape around that shaft and the problem has been silenced. I may do something more elegant at some point, but this was too easy and 100% effective. And it has lasted several trips. PM me if any questions or you want more detail.
DAT in TX
2018 Vista LX 27N
2015 Jeep Rubicon and ATC Open Car Hauler