Weimaraner,
I'm curious about why you are set on Disney? I'm a huge Disney fan, but Marriott and Starwood both have timeshare properties 5 - 10 mins outside the Disney main gate. You don't even have to get on I-4, so you miss most of the traffic during the busy times. I'm guessing it is because of either transportation or the dining plan? The dining plan may or may not be worth it and Orlando has relatively inexpensive car rental rates. I personally don't think staying on property is as convenient as some others do. (You still have to wait for the transportation. It usually goes to different resorts for pick-up and drop off before heading to the park. Sometimes it's crowded and you have to stand on the bus, boat or monorail, which I've done in the past holding a cranky toddler. Depending where the stop is in relation to your room, you may still have to walk across the resort. The process can take almost an hour if you leave the parks at closing or after the parades or fireworks.)
If you stay in one of the Starwood or Marriott properties, you will also be very close to Seaworld, which is fun for a day or two, especially at your daughter's age now. Universal is pretty close also. When your daughter gets a little older, she may be interested in going to see the Harry Potter section. My daughter, 12 now, is an adrenaline junky and likes the bigger coasters at Universal. There are also a few dinner show - Arabian Nights, a pirate themed one, and a medieval themed show. If your daughter likes horse, she would probably love the Arabian Nights show. I took my girls scout troop there when they were 8 or 9. The girls loved it. You can find buy on-get one free deals for those type of places.
There are tons of restaurants in the area around Disney. There are tons of specials - kids eat free, 2 can dine for $20, etc, that make it much less expensive to eat off Disney property.
Just my two cents. I live 2 hours away and I have had annual passes for the last 13 or 14 years. I've been there all times of year with all age kids. If you can, I'd travel to Orlando off season while your daughter is younger to minimize wait time. I can't tell you how many times I've seen crying, screaming, or even very sick kids being drug around Disney because the parents try to squeeze too much into a short amount of time and run their kids ragged.