Don't despair! A co-worker adopted a kitten from me who was so terrified at first that she hid behind a piano and cried for a couple of days (the kitten, not the co-worker)--my friend had to have someone come over and help her move the piano to get poor little Boo out. But Boo got used to her new home and now she's a completely happy kitty.

I'd keep B in the bedroom for awhile, to let her get comfortable in a small space first. When I brought Bob (who was most likely feral) indoors, he spent several weeks on the enclosed back porch before he got brave enough to move into the bedroom. From there, he started exploring the rest of the house. Now he's still shy of other people, but he's a perfectly comfortable house cat.

One thing I did with Bob was to spend a lot of time sitting on the floor--first on the porch, then in the bedroom--talking to him quietly. At first he kept his distance, then he'd come just within petting distance, and eventually he started curling up in my lap. With some cats, it takes a lot of patience--and cats don't like change--but she'll come around.