Rattling passenger side, Access Cab

Hello!

I have an SR 4 cylinder access cab, the work edition, and while driving at highway speed the passenger side has this annoying rattling/vibration going on.
It seems to be rattling around the access door itself too, but not 100% I haven't been able to pin point it really.

Has anyone dealt with this, and what are the steps to get whatever it is to stop rattling? I've never dealt with anything like this, but I am assuming I will have to remove the door panel to either tighten stuff or add some kind of insulation maybe?

 

Mine caused by seat buckle tapping around, take the buckle insert into the slot above and all the noise is stop (see yellow line for an idea).

 

My door latch rattles sometimes on my driver's side, could be doing the same on the passenger side for you.

Fixed with some tape suggested in another thread since it never wants to rattle for a tech at Toyota.