I think we should leave the rotating palm trees out of this discussion with their strange predilection for Captain's seating (some silly argument about torque, I recall)!
You basically 'mount' where the access is (makes 'three in a bed' a challenge.....). If Mr XXX put footsteps on the left, that is normally where you get in. If groundcrew put steps on the right ditto. If a side-by-side, one normally uses both.
With 'walk-rounds', the main thing is to remember where you started and finish up there again.