Is this your first OTTB? If so, you probably need to go back and read up on what to expect, or talk with other people who've rescued them. I'm sorry if I'm repeating things you already know, but here's what I'd suggest.
I currently ride a 9 year-old OTTB mare who hasn't been on the track for at least four years. Like other former racers, she would have benefitted from at least a good month turned out in a pasture learning to be a horse before you even think about working her under saddle. 60 days is better and longer doesn't hurt.
A lot of OTTBs don't understand basic things that other horses are trained to accept, like crossties. My girl can't handle standing tied. If I bathe her, I have to hold the lead while someone else hoses her. If she's tied, she backs up, hits the end of the rope and all hell breaks loose. (If she was my horse, I'd already have dealt with this problem--but the BO doesn't think it's worth the mare's time to learn. Grrrr.)
I'm not at all surprised that your mare took off, or that she's spooking, or that she's smashing her head on things. It's going to take time, serious time. Start at the beginning: let her calm down and get off any drugs and grain-heavy diets that might be cycling through her system, then slowly introduce her to new sights and sounds. Who knows what she's experienced or what she's never seen before? She probably hasn't even been ridden under saddle the way you ride (think about the position jockeys adopt when they're mounted: even your center of gravity probably feels weird to her). I found this manual to be pretty helpful: http://www.leightonfarm.com/RetrainingManualMAY2010.pdf
Good luck. OTTBs are *wonderful* animals, but every one at my barn has its own unique quirks that you have to be comfortable dealing with. These horses tend to be very sensitive and sweet, so working calmly and quietly with any issues that arise will be a good place to start.