That's a good deal. We fly from Chicago down to MCO a couple of times a year. If we can fly for under $200 a person, I am happy. I am guessing you are flying Southwest, which means no luggage fees. Have we paid less, sure but only with really strange circumstances.
Free dining at Disney is a good deal, where else can you get food and a hotel room for your family for that daily price?
If you are going to rent a car, check out the mousesavers website for deals, if you plan to take the "magical bus" you won't need that expense.
You may also want to consider staying longer on property, extra days on your tickets are about $3 per day. If you have free dining, the only extra cost would be hotel nights, which I am guessing you are staying value means less than $100 per night.
For example: if your schedule permitted you could extend you vacation by hotel room 2 X nightly rate (I am using $100) + 4 times $3 times 2 days. Grand total $224.00, the extra days may make your vacation a little less hurried.
Have a good trip.