Re:
If where you are staying is considered inside the park shuttle buses abound to get you most everywhere you would need to be. If outside the park a car is the only way to go.
If in the park, I highly recommend the meal plan, if memory serves, saved like 40%.
Agree with one day per park. Magic Kingdom is the original and will most likely be your daughters favorite(they offer a princess breakfast, at a fee of course). Bring loads of sunscreen, remember it is Florida not the U.K. Most importantly relax and enjoy yourselves. Not sure you will see clowns though.