Im really big on being around my horses when I have nothing to ask of them =) A lot of people who have non-rescue horses make the mistake of only going out to their horses if they want something (to ride, to worm/give shots, etc)... Just go out and be around her. Horses are curious little things... More often than not, when i've worked with an abused/neglected/beaten/never handled horse and IGNORED it outright... they would come up to me with this look on their face as if to say: "Hey bub, everyone else wants to touch me, brush me, lead me, vaccinate me... why don't you? Am I not good enough for ya?!" LOL
I wouldn't go as far as to say never catch her unless she wants you to... because I personally think that is giving a 1,500 lb animal a little too much "control" over ya =) I agree with the concept of "dont go out and trudge up to her, and grab her to give her shots" but I think the best way to approach this whole situation is:
Try to be around the barn at the same time every day. She wants consistency in her life... if you start to become that consistent thing, she will automatically be drawn to you because horses really enjoy someone who is consistent with them... Neglected horses need consistency the most!
Hang out with her, get her interested in you without you asking for anything from her (not even to lead her).
When she accepts you being near her in her paddock/stall/pasture start very small by just touching her. If you see her begin to shy away briskly (but not startlingly so) pull your hand back and take two steps backwards (also briskly). Miakoda was increadibly hateful of people when I got her.. but she LOVED playing the mirror game with me.. She would lean to take a step back as I approached her, so I quickly took 2 steps back and before she ever lifted her foot to move away from me, she had actually taken two steps TOWARDS me.. Horses are so awesome like that, LOL!
Then once she enjoys your touch, and your company, if she is kept out with a halter on, just clip a leadrope to her and stand there. Don't ask her to lead, just stand with her and pet her. Then unclip the leadrope and leave. Don't dottle, don't try to pet her afterwards, just go.
Once she enjoys the touch, company, and is tolerant to the lead, take her out to do something she wants to do.. perhaps you can hide carrots around the barn and have her find them (Skippy! Loves that!) or, just find a big patch of grass and let her munch away! Always, ALWAYS put her away happy!! =) Because that's what she'll remember the next time ya come out to get her ^_^
DO NOT work on any of the bad habits yet!! Bad habits require swift correction, and for a horse in a fragile state of mind, the correction will almost always be related to in a negative manner and it will completely undo your work. Once she becomes a happy, person loving/respecing horse, you guys can begin working on fixing the kicking, biting, etc. Just try to work around it for the time being, or avoid doing things to instigate the behavior... if that's possible
If at all possible, I'd really recommend stopping the food bribing, because then she may just view you as a food dispenser. You don't want a horse to come to you because you have food... because they aren't really coming to you, just to the food :) I understand that at certain times we all have bribed our horses (lol!) But a horse will respect ya more if you don't use food to grab 'em. Charity was a feral, wild little thing when I got her and I spent 15 minutes staring her down in the corner of my field to catch her. I was SO CLOSE to getting some feed, but I resisted, and now I have a better horse because of it!
The whole process will take a while, at LEAST a week of constantly working at it... so be patient! As someone above said, if you rush it you will erase ALL your progress. This is also much easier to do with your own horse on your own land... because where she is at now, someone else might trudge into her stall and grab her which may undo all the work you had done (it all depends on the horse)
I hope that all makes sense! Best of luck!! Keep us posted!