If they have more than one office are the records electronic and shared between them?
How liberal are they with prescribing antibiotics? Most doctors will prescribe them for everything even when it's not an infection and they won't help at all thereby helping to create antibiotic resistance.
How far in advance do you need to schedule appointments and how flexible are they with changing if you need to?
One thing I found important was seeing if they actually liked kids. It's not really a question you can ask but more of a feeling you get from just talking to them.