Just a warning ...
We do bring our stroller, but my daughter is 2 1/2 and doesn't like to ride in it. It's a STRUGGLE to get her to ride. I bought one of the monkey back pack leash things, well actually my parents did after they took her to Disney, so she is attached to us at all times. She really really likes to walk at Disney, and even though half of the day the stroller sits empty, it's nice to have with you. We have to let her get in and out of the stroller on her own and walk as much as possible, or you get an amazingly festive tantrum. I have to say, Julie has gone about 10 plus times, so maybe she is just more used to Disney than other kids, who knows ...
If you haven't gotten their hair cut, I recommend doing a first haircut at the Mainstreet Barber shop. We got her hair cut for the first time there last year and it was darling. We will be going back this August for her second haircut, it's that worth it.
Let your children take the lead, and just watch them. The last time we went, in May, we went for the Flower and Garden Festival. My daughter climbed up to the top of the playground near Test Track with Wendy. She spoke to Wendy for about 10 minutes, it was adorable. If your children know anything about the characters, remind them while they are in line to speak with them. My daughter was afraid of Hook and Smee, but in line I asked "Remeber when the croc gets Hook?" So, when we got to him she said "Argh, croc's gonna get you!!" He pretended to be scared of her, which broke a lot of the tension she had of him. If you ask her about Disney right now, she'll go on and on about Hook and Wendy, they made such an amazing impression on her.
Let me just warn you, it's truely amazing to see your child's face when they see the castle for the first time. I don't know if it's the same for little boys, but the look of pure joy and wonder when they realize who that castle belongs to ... sigh. My daughter refers to our house as Princess Juliette's Castle, which probably means we should lay off the Disney trips for a little while, but it's amazing how she brings the magic home.