I'm with Jon the concierge service. Concierge at the Polynesian is particularly wonderful. You basically get breakfast and lunch/afternoon snack at no additional charge, then you can choose whether you want to eat supper at a restaurant in one of the parks, there at the hotel (or one of the other hotels) or eat their heavy hors d'oeuvres that they put out in the concierge lounge instead. They also put out alcohol/cordials in the evening as well as desserts. In the morning, prior to heading to the parks, you can grab a few complimentary bottles of water to take into the park with you and just refill them from the water fountains in the park and not have to shell out a ridiculous amount of money on water. The concierge service totally makes up for the price by the number of meals and snacks you WON'T have to pay for in the parks. You're also going to want the Park Hopper option on your multiday tickets. This will allow you to visit multiple parks in the same day. I also do not recommend the Meal Plan if you go concierge for the reasons I stated above - there's just already plenty of food options available to you in the concierge lounge, then you can pick and choose which sit-down restaurants you want to visit.
With a seven year old, I recommend staying at one of the monorail line resorts (Polynesian, Contemporary or Grand Floridian). She's going to want to go to the Magic Kingdom more than just one day. If you're on the monorail line, it's soooo simple to walk onto the monorail and skip over to the MK for a couple of hours. If you go during the Christmas season, all the decorations are out and the parks and hotels are simply stunning, so make some time just to visit the other hotels and take in the decorations. If you choose to stay at a moderate or value resort, you won't get the concierge option, and while they are lovely too, you will need to factor in a little bit of extra time for bus travel (although the bus system works almost flawlessly).
You'll want to plan out, in general, what your schedule is going to be ahead of time. We always plan based on what our nightly entertainment and supper plans are. For example, if we want to take in Fantasmic at MGM (I still call it that), we would plan to eat a sit-down supper a couple of hours beforehand in that park (we like The Brown Derby). If we want to take in Illuminations at EPCOT, we'll plan dinner at one of the World Showcase restaurants. Some of these evening shows have dinner packages you can arrange that gives you your restaurant reservation and reserved seating for the show. We did that the last time we saw Fantasmic and it was wonderful to be able to enjoy our supper and stroll right past the crowd waiting to get in to the theatre and go straight to the best seats in the house.
They have a nice service at all the parks now where the Disney photographer takes your family's picture at certain photo worthy locations (in front of the castle, in front of the tree of life, in front of the sorcerer's hat, etc) and they give you a card that allows you to access your photos online later and purchase which prints you like. It was nice not to have to ask strangers to take those particular pics and to later be able to pick and choose a few really great shots. Just a convenience.
For your little girl's sake, please schedule a character breakfast. If she's into the whole princess thing, do your best to get the princess breakfast in the castle. It's a really special thing for a little girl. We took our girls when they were 6 and 8 and they were blown away by getting to have some one on one time and pictures with all the princesses. If she prefers the regular characters, then Chef Mickey's at the Contemporary and The Crystal Palace in the MK are the best breakfasts for the likes of Mickey, Pooh, etc.
Make the most of your Extra Magic Hours. By staying on property, you get to enter certain parks early or stay later on certain days. The crowds are light and you can ride certain rides over and over. I also recommend making smart use of Fast Pass for certain rides to save time.
For information and planning purposes, I highly recommend
www.intercot.com. Get yourself an account and dive right in. If it has anything to do with Walt Disney World, you will find it there.
Any questions between now and then, please feel free to PM me.