The missing path is one that she called (and I think is a suitable title) the Self Improvement path. It is one where the individual focuses on improving themselves either intellectually, physically, and spiritually. It may be learning about the arts, reading a wide array of topics, going to classes and learning new skills. It may be exercising, eating better, presenting themselves better and becoming stylish. It may be serving others, going to church, prayer, reflection and meditation. This path is about becoming a more well-rounded person and focusing here can improve the other areas of life. The other advantage to this path is that it can give you a better self esteem and autonomy. You can be content by yourself.
This path has a lot to do with your down time. In fact, I see this as very much related and very much opposed to the Selfish path. The Self Improvement takes your time off and will typically improve the quality of your life, while the Selfish path is potentially destructive. Self Improvement will benefit you in the long run while the Selfish is usually about immediate satisfaction. If vice appears in the vacuum, then keeping yourself busy with other endeavors that actually build your spirit, then you are less likely to spend that time destroying it.
I should point out that there is admittedly an occasional overlap between the different paths, because the Adventurer may pick up a variety of random skills and are exploring the world out of a spiritual drive, but I think there is a distinct difference in that one is going out in the world and discovering truths from others and different cultures and the other is to themselves trying to become better able to make it in the world. There are similarities, but they are differences.
I'm sure I will be thinking about this stuff for a while, because I'm a nerd like that.