Seriously, if I was put on a deserted island and you're wondering what my first thought would be ? It would have nothing to do with trading. Reality, I'll be thinking about having a boat with sails, food supply, fishing equipment, survival gear, communication gear and a horny beautiful woman. If you say I can only have "one"...then it would be the horny beautiful woman because everything else I can manage and build on my own considering this thread is in the psychology section. That will be my setup.
You could probably still make money teaching it slow. Installments or leafs or belts. Maybe a black belt trading academy. Oh wait...taken!
The first thought,meaning how(what,what method,your risk,disciplin,etc..) would you trade,the point is not about island at all.Metaphorical island,you could be on an 'island' in your appartment.