Am I doing the right thing with my new cat?

I have recently acquired a young (9 months or so) cat from a friend who is moving away.

She comes from a good home with two other cats (who are being re homed with the original owners family but my cat, Marmite, was unable to go too) and has not been mistreated in any way.

Since she has been at my flat she has been hiding a lot, which was frightening at first as I could not work out where she had gone! Now I have worked this out and I know that she is safe, she is eating well and using the litter tray etc but she is very nervous around me and will not come up to me, unless I give her a treat, and even then she won't let me stroke her and runs off if I move.

She is much better than she was and most nights she will come to the door of the living room and look at me, she is also exploring rooms both during the day when I am at work, and when I am at home, as long as I sit still and make no sudden moves! I have left catnip toys about the place and made spaces for her to snuggle up etc.

Also she was allowed outside in her old house however as she is new to the area I have decided not to let her out for about 6 weeks, or until she is content at mine

Is this normal, am I doing the right things and do you have any advice that will make her feel more at home without frightening her? I have had her for 2 and a half weeks.