Looks like there are many reasons to get creaks. I noticed this too and experimented with a few things. Turns out it was the right passenger door.

To test this, I tried having the passenger door slight ajar during slow weight shifts - no sounds whatsoever.

If I drive out of my parking space as usual in the morning (up a ramp), I'd hear the creak.

Somehow I don't hear it once the car warms up (or I just don't notice it).

It's very annoying.