I've lurked often in this thread too. We're leaving tomorrow to go to Disney World! We're staying for 5 nights, at the All-Star Music. It'll be me, DH, our 1 year old DD, and my mom and dad. I think 4 adults should be able to handle one toddler.
To the previous poster who asked if 2.5 was a good age, I don't think there's such a thing as a kid being too young to go to Disney! Sure, they may not remember it, but they'll have a blast while they're there, and will love looking at the pictures in a few years. Plus, I love Disney, I'm not going to sit around and wait until she's old enough to remember it!