Sounds intriguing! Out of curiosity, is the player an adult or a child? I haven't tried with a single player, but rather my two oldest kids and that worked well enough, but I also created a character for myself, as a a "skill resource" and to provide some story assistance if they'd get stuck, but is otherwise passive.
As for playing with a single player, I would myself probably ask the player to put some points in Charm or Contact, so that they can get help from others - either other kids or adults. Either that, or play out mysteries suited to that particular kid's skills, even if that could be limiting. Perhaps the kid has a dog that can assist with a few skills, such as Force, Charm or Investigate (under certain circumstances)?