Freight Drivers:
Assume Left Seat, Rt Seat (& F/E, if appropriate) are on oxygen. Most long-haul is augmented or double; there are loadmasters, mechanics, sleeping relief crew on-board. I would get the cockpit safe (on Oxygen), then GET DOWN, as the non-flying guys may be asleep (permanently, if the cockpit guys have attitudes demonstrated in previous posts). Unless you know nobody is in the aircraft except those present in the cockpit, I wouldn't think twice; I'm down! Then check. The sequence is critical.