What questions should I ask when calling references for an in-home daycare provider?

I'm thinking of taking my daughters part-time (2 days a week) to a woman who is just beginning a small preschool/daycare in her home -- or should I say homestead. I really like it because she's passionate about time outdoors and they live on 36 acres with animals, kids getting their hands dirty playing outside and with arts and crafts... She works part-time in a daycare, I toured her place and she seems well-organized and like she has thought this thing through. But my girls would be her first kids. I feel like an idiot, though. When I call her references, what kinds of things would you ask? I feel like there are obvious things but I don't want to miss any important ones... since she is, well, a stranger. Thank you!!