Can you post a pic? That'll help determine how bad her situation is.
For food, without seeing how bad-off the snake is, my general recommendation would be to start on the small side of what you'd normally feed a snake that size if she'll take anything on her own. It's just easier on their systems.
I don't have a lot of experience with when to start assist-feeding. Since it can be pretty stressful, I'll let someone who knows more about it answer that.
Glad you got her, hopefully it's not too late![]()