Hi there Erica!
Walt Disney World is a
very infant and toddler friendly vacation
destination and as a parent, you will be amazed at how well
planned out the theme parks are for accommodating the under 5 crowd!
Keep in mind that children under 3 years of age are granted
free entry
into all four Disney Theme Parks and the two Disney Water Parks! There are also wonderful
Baby Care Centers
available at no additional charge throughout the Walt Disney World
Resort to help you with any infant changing or feeding needs.
Check out this link to the
"Traveling with Little Ones" in-depth park guides, character meet-n-greet details and kids programs. There is also a listing of the Disney theme park attractions that do not have a height requirement and can be experienced by an infant.
For your four year old, check out this unofficial resource www.wdwinfo.com. In the search engine at the top of the page, type in the word "height" and you will find the link to a Height Requirement Calculator. Simply type in your preschooler's current height in inches and then submit to receive a listing of theme park attractions accessible to your child.
Lastly, you may wish to consider utilizing the
Rider Swap option available at select attractions.
Rider Swap is when Guests take turns waiting with youngsters too small
to ride a certain attraction, then "swap" with another adult Guest from
their party to experience the ride without standing in line twice. Just chat with a
Cast Member at the attraction for additional information and assistance.