This little bugger has been hanging around my SO's workplace. She's absolutely attached to us and would show her belly every time we try to pet her. And it's not a trap! She loves belly rubs.
Now we wanted to adopt her for a while and have been taking care of her, vet visits, vaccines and all. We really want to have her in the house but we already have a cat (who'd love some company) but house rules allow for just one.
We also have a yard which is cat-friendly with shelter, places to sleep in, climb and scratch, and not directly on the street.
We know she's used to her environment and our worries are that she'll run away and try to go back to her old place, which is right on the street where her sister perished by a car at an intersection.
How can we go about this?
She's already acclimated to you so I would suggest that you just bring her home and see what happens. Stay outside with her for a couple hours at first so she knows you're there. Also I don't know that the climate is like where you live but if you live somewhere cold please get her a little heated house and heated water bowl. The heated houses are more like a heated pad than actual heating but will help keep her safe and comfortable in winter.