I feel pretty good about her explanation—she was ousted from her comfortable position and driven out of her tribe during a takeover, and she's been holing up in the Rusty Dragon for a few years at this point "planning her next move". Her communal-ness is actually part of what's driving her to adventure—in the absence of a tribe, she's gotten very attached to the Rusty Dragon crew, though she obviously will never say it outright. She's not in it for the adventure, she's here because she doesn't want to be left alone.
... That, and she doesn't think the people of Sandpoint will continue to put up with her once Ameiko, Sandru, Shalelu and Koya aren't around to keep an eye on her. :P
If you think it needs more, let me know! Kinfen does not have to be a kobold, but I think she's much more interesting as one—for instance, her being a painter who's unable to see color, her intense fascination with a world she doesn't understand, and her being extremely ill-fit to the environment she's been dropped into and then being pushed into a dangerous and difficult journey.
I did consider Koya for the crush, but if I make Kinfen Old age, her Strength drops to 3!