(((NSW))) I also struggle with getting into the middle of my addicts' "stuff". My sponsor would tell me to pray about it and to ask for clarity around this situation. Like me, she often asks that the right path be made soooo clear that there is no mistake. Then she tells me to be "hyperaware" of what it going on.
For example - if the meeting with your daughter falls through - even because of traffic or lack of a babysitter or the car won't start - be aware that may be a way your Higher Power is letting you know where you need to be.
I like Done's idea... tell her what's going on and give her the option of being dropped at rehab.
I wish you well. (((hugs)))