Love all the advice given so far. One thing that we were not prepared for was the school's assumption that our child's behavior issues (they call 'reading all day instead of participating' a behavior issue) are the result of bad parenting, so you may want to prepare yourself for that battle. They wanted to coach us on how to parent instead of discussing appropriate work for our child. We also (still) keep getting the "until your child finishes the assigned work, I won't provide anything at a higher level" even after presenting IQ test info, portfolio stuff, etc.
Grinity's right: At your son's age, you can't count on him to play along to get to the good stuff. I grabbed a great analogy from this forum in response to their point that our child has to learn to do things that they don't want to do. I explained that we agree - that's what making her bed and brushing her teeth are for. We take care of that important lesson at home. However, she is at school to learn other things. And now for the great analogy I stole from someone here: I explained that while most people balance their checkbook even though they hate doing so, these are the kinds of kids who, if allowed to flourish, will create the next online billpay because they hate the tedium of paying bills.
I would add that you can also familiarize yourself with the district's mission, vision, etc. You can use a few quotes from their own documentation saying things like: "I know that we have the same goals. The district's mission even stresses 'individualized education', so I'm sure you want my son to learn what he needs to learn. I'd like for us to work together to find the best and most cost-effective way to ensure that he learns at least half of every day."