Hi Jane!
I think that you will be pleasantly surprised by just how much the four of you can ride together! In fact, the vast majority of rides can be experienced by all ages. For example, It's a Small World, The Haunted Mansion, Pirates of the Caribbean, Jungle Cruise, Peter Pan's Flight and Snow White's Scary Adventures - and those are just at the Magic Kingdom!
Don't despair! You can still enjoy all of the "big-kid" attractions by utilizing Disney's Rider Swap system. Essentially, one parent goes on the ride, while the other parent watches the kiddos. The parents can then switch places without much of a wait time at all. The official Disney World website has a great section that deals entirely with
traveling to the parks with little ones. You can even download special maps that highlight all of the "toddler-friendly" attractions.
While you are online, check out this
great info on celebrating your first time at Walt Disney World. Also, once you are there, be sure to stop by the Baby Care Station located within each park. Here you will be able to feed the baby, change diapers and relax a bit in the air-conditioning. So grab your Baby Bjorn and stroller and get ready to hit the parks running!
Much pixie dust,
Jackie S.