Returning to the solo vs. sole bit I think it worthwhile highlighting that there is still a great difference, regardless of whether the second person is a pilot or not. Those of us who have flown any significant distance/time know how boring and demotivating the task can be. Having someone with you who can laugh, argue, be a punchbag or just merely chat is a godsend. personally, I couldn't contemplate the loneliness of a 13000 mile flight with only a radio as a means of communication. I know it sounds a bit insignificant but the presence of another individual can make such a difference.
So, Ms TCT your flight wasn't really a challenge. I'm sure I could find some specialised travel/holiday company who could give me exactly the same experience at an exorbitant price. Not bad work if you can get it.