Help with 13yo

Not 100% sure I have put this in the right section, so feel free to move if necessary. Some of the background is in another section, but will post it all anyway. Just over 3 weeks ago, my old vet rang to ask if I could take on an oldie as her owner wanted her pts as he had basically had enough of her - he made out ot the vet she was destructive, but just said to me she is to tying!! He said that he couldn't stroke or brush her but she wasn't vicious, which i found odd as she was letting me stroke her in the carrier. I had to cage her when she got here, as the foster in my cat room dislikes cats, and Ginger likes sleeping in teh bathroom, which is my only other spare room. When she is in the cage, she is fairly affectionate, she will let you stroke her, and will actively butt you for more, yet as soon as you let her out of the cage, she tends to dash straight for the stairs, and will tolerate a stroke on the head for seconds, but will then lash out, and likes to try and bat legs and cats that walk past her. Yet when she is near the cage, she will let you pick her up, she growls, but tolerates it, and I have managed to clip her claws, put her collar back on (he took it off, and it came in her bag of things) and deflea her, although I did crush the wormer and put it in her food, so doubt she got a lot of that. My main question is that she hasn't really changed much in 3 weeks, so at her age, is it worth me trying to do anything with her, or just leave her to her own devices? She is currently on the rehoming list, but I am not sure how well we are going to do rehoming her, and again, is this a viable option with her age and her being rather anti-social, or should i just suggest to the rescue that I integrate her here, and allow her outdoor access (I do live in a safe area for cats to be outdoor, and she has always had outdoor access), I am wondering if she will be happier and come round better with that than me having to confine her at certain times as mine are allowed outside?

It seems that maybe you should integrate her there and let her live out her days with outside access and limited access to your other cats. You never know what has happened to her before, her previous owner may have not treated her well. She may turn out to be a great old gal in new surroundings. Please keep us posted on what happens with her.

That was my way of thinking - although I dont really want another long termer. She isn't too bad with my cats, Molly will spit at her, but the others will walk past her, even my rather timid male, who normally avoids cats!! She was apparently destructive, but I haven't seen much sign of that, and he had no toys or anything, so I dont think he did anything to her, just a lack of interaction, so at her age, she isn't used to it. She can be affectionate though, but only when she is confined and wants out, when she is out in the house, she doesnt' care. I thought she would be different here, and she is, I did manage to quickly brush her last night, and I had already put her collar back on (in case she is allowed out) and de-flead her, plus stroked her a few times, at least two things her owner said he could never do.

Does she enjoy having some hiding boxes? I had received excellent advice from Hissy on taking on an abused cat that also worked with a semi-feral that in less than 3 months changed from an orange-blur to a growling, snarling fizz ball to a shy stray who is now a real lover-boy who will actually come inside and let me pick him up! It is so amazing - people are actually doubtful that it's the same cat. The Feli-way spray really helped. Also, I gave the outside cat, TommyScott, some boxes with holes cut out ( a homemade version of a kitty condo) and he really appreciated those.
It sounds like you are making great progress, with being able to stroke her and get her de-flead;if you are able to let her finish her time with you, rather than re-home her,she might just come around yet. Please keep us updated.