Stay on property. It makes your entire trip so easy. Disney picks you up at the airport and delivers you back at the end of the trip. You never need to rent a car. We went last year mid January and stayed at Animal Kingdom with a Savannah view room. It was really cool. Our twins were five at the time, so they were the perfect Disney age.
You need to book your reservation soon. It's not that the hotels will sell out. You want to get a reservation to have a meal with the Princesses. It is the best way to see them all. We had lunch at Cinderella's Castle. Our girls LOVED it.
Be sure to buy your daughter's princess dress at Target. It's way too expensive to buy it at Disney. All the little girls wear princess dresses to a meal with the Princesses.
Also, book a meal at the Crystal Palace. This is where all the Pooh characters are.
As soon as you arrive, get your daughter an autograph book (bring several pens) She'll want to carry it with her. The characters always pose for a photo and autograph the books.
The character meals are totally worth it. They are the best way to see the characters and get the photos/autographs.
We bought a meal plan for the convenience of it. Everything -- meals, park tickets, etc. -- is ties to your room key. You don't need to carry more than a couple of dollars.
One mistake we made is we didn't eat at enough of the fine dining restaurants. We didn't think the girls would like the menu, but DUH, it's Disney. Even their best restaurants have a kids menu. This year we're going back and we won't make that mistake again.
You are wise to take her out of school for a few days. It's what we did last year and what we'll do again this year. It's not quite as warm as if you go in the summer, but trust me it's worth it. I've been to Disney in June when you have to wait an hour to get on the teacup ride in 90 degree heat. It's not fun.
One more thing...limit the time you spend in the park. We found that six hours was our max. I know you are spending a lot of money, but it's miserable when the kids are overtired. It's much better when everyone leaves before the kids are overtired. We altered our days so we were there early one day and late another.
Enjoy your trip! It's so magical for the little girls.