My sister and I had five boys so all of our trips until recently were boy-oriented. 2 years ago we took her almost 5 year old grand-daughter at the end of May and the experience was so different. With boys we could get away with one character breakfast (where eating was as important as meeting/greeting) and maybe 1 character photo with Buzz or Woody if the line wasn't too long. Gdaughter was a competitive autograph hunter of Princesses even at that tender age and loved each and every interaction she had. Almost all of our first 3 daily fast-passes were taken up with the character meet and greets because we were too late to book the Princess breakfasts.
Of course she wanted to dress as a Princess -- luckily our local store stocked a variety of Princess dresses at prices way below Disney's so we brought a couple of the prettiest in our luggage and probably saved over $100! Beware, those dresses are very scratchy and not made for all-day wearing in Orlando heat and humidity, so we always had a change of clothing to get her back into shorts and t-shirt by 11am.
The other big difference was the time it takes to get a little girl (long hair etc) dressed and out of the door in the morning, compared to heading out with little boys who are, mostly, less fastidious about their look!
Enjoy your time with your granddaughters.
