Hmmm, sounds interesting! Dunno precisely how well this type of character would work, but what I've got in mind for something like this would be a Loner traveler taking jobs as something of a soldier of fortune-rations and a warm bed today for manning the walls of a Govvy Shelter, only to hoof it the next day to clear a lurker infestation for some greaser's to sleep easy and collect a box or two of ammo. Chaotic Good type; prefers against killing humans besides marauding raider gangs, but always up to help protect a settlement, knock some lurker heads together, or even so much as ferry supply shipments to make sure everyone can eat for the next week.
...As long as s/he gets paid, of course.