I think that Disney World is probably one of the baby friendliest places! We took our son to
Disneyland when he was only 3 weeks old and had an amazing expereince. We took him to Disneyworld when he was 5 months old and had an even better experience. Consider mailing some supplies like diapers ahead of time. We checked one bag entirely for our baby with diapers, food, essentials for the week, and a case of bottled water and that helped a lot. Make sure to bring a stroller...Also, there are really nice baby centers located in all of the WDW parks. They have changing stations and sell extras like jars of baby food and formula. Just make sure to bring lots of socks because our little guy kept losing his and some of the characters won't take pictures with your child unless they have socks on so we kept having to buy Disney socks at $7.00 per pair. That adds up!!! Remember to bring things like Tylenol and a nasal aspirator. We lost our nasal aspirator and could not find one anywhere. Even concierge couldn't track one down!!! Sometimes the weather difference can make allergies act up and that happened to our son.
There is a great feature called baby swap where mom and dad can take turns riding attractions while the other holds the baby and then swap. That way you won't have to stand in line again. There are so many baby friendly rides though. Our son loved "It's a Small World" and pretty much everything in Fantasyland. Have a great trip!!!