The problem with asking us for options to help you save $ is that you appear to have already made firm decisions about where you want to stay, what you want to do and how you plan to get to Orlando.
For example, if you had not already decided that you want to stay at Animal Kingdom Lodge, we could make suggestions about pros and cons of less expensive WDW resorts. As for the Animal Kingdom Lodge, do you know that it is not actually inside the Animal Kingdom Park? It's about a mile from the Park, but does have some animals in the surrounding savannah.
And are you really going to drive from Minnesota to Orlando, stay on site at Disney World and only spend a day or two at one or two parks? That's pretty much heresy to all of us DisneyWorld nuts on this board. You're taking your pre-teens to Disney World but won't go to Magic Kingdom?? But financially doesn't make much sense either. After two days, Disney World tickets get progressively cheaper the more days you buy. Thus, for one day, an adult ticket is about $75; for two days is $148; for three days is $216; for four days is $225; and five days is $228. Sea World tickets are $57.95 for one day if bought 7 days in advance, according to the website.
Also, have you checked for cheap flights? You are going to spend at least half of your vacation driving the 1600+ miles, which Yahoo maps says will take about 24 hours one way! And, as you say, with the price of gas and your having to stop at a motel(s) in both directions, all that driving is going to be expensive as well as exhausting and boring. I suggest you post a query on the Transportation Board (of Dis Forums) asking folks for info about cheap flights from Minnesota (or airports near you) to Orlando.
Since you already know more or less what it will cost to do the trip with your current plans, the only way you can save money is to change your plans. So why don't you start over and ask a more open ended question in a new thread, such as how you can do the trip on your budget, whatever it is? Include the size of your family and the ages of your children. I guarantee you'll get lots of great advice from very knowledgeable folks.
Allie