I think indigo's links are great. I had a couple of thoughts, based on our (unsuccessful) experience relocating to the Northeast a few years ago.
1. Do push the schools for specifics. So many things sound great but are not what they seem. Our school touted its Mandarin program (3 days a week! Starting in K! Kids are writing characters by 3d grade!), but we arrived to find it a joke: the school could not keep teachers, and the students (except for a handful) were disruptive and disrespectful (not the teachers' fault). It was something for the school and parents to brag about without any substance.
2. Ask for specifics on acceleration and differentiation. We got a lot of soft talk about differentiation, but it turned out to be just some leveled reading groups and a little extra math homework. The math was so bad (Everyday Math) that most of the high-performing kids went to outside math classes. The reading was OK but still grade-level. I would ask for *specific* stories of what they have done for g students working at several grade levels ahead.
3. Written materials, IME, are next to useless in capturing what happens on the ground, which depends critically on teachers and staff. That means it's very hard to get a real sense of what is happening. Parents, too, have only their own experience, and so when they say "X is an excellent school," what they mean is that (a) it fits their kid or (b) they're putting a happy face on a mediocre situation that they will only confide in you after you move in!
4. One exception to 3. might be to ask about math courses in 6th grade and above. Can a 6th or 7th grade take Algebra? Is Geometry available before high school?
Good luck! As a shorthand, and others on the board might disagree, beware Everyday Math.
