K.W.
Last January, my family of four went for around $2000 out of Midway airport. My son was only 2 at the time. Because of this, we did save @ $250 by not having to buy him a park ticket. My daughter was 4, so we had to get one for her.
I saved money by flying out early Saturday and returning on Wednesday evening. I paid under $200 for each airline ticket. We stayed at the Pop Century Disney Resort, which I highly recommend. We got the non-peak rate of $80 per night. We did not do the dining plan. I found this required to much planning and required you to be more on a schedule, making sure you were at your scheduled restaurant at the correct time.
We got a 5 day park ticket without the hopper option. There is so much to do in each park, I cant imagine going to two parks in one day, but I know a lot of people who do this.
Anyway, that is my two cents. Enjoy the trip. We had a great time.