I'd probably live out a silent hero-type life, wandering the wastes, with all that dusty gear and that trenchcoat and maybe a nice pair of sunglasses. I'd help out people I saw, and slowly gain reputation, but not make many, if any personal connections to anyone, or anything but my rifle, knife, and revolver.
If I
had to fight, I'd gather a ragtag army of people who know of me from my good deeds, and take over Vegas.