Traveling With an Infant - Touring the Parks

There are many, many things you can do to make sure you have a great time in the parks with an infant:

Minimize the baby's exposure to the sun. Furthermore, using sun block on a baby that is under 6 months old can be dangerous (I don't remember why, but again, it was the doctor's recommendation). We made sure to use the sun shade that's built into the stroller all the time. We also avoided spending long durations of time in the sun with the baby. Instead, we'd find some nearby shaded area if any of us were out with the baby for any length of time (during a baby-swap (see below), for example).
Mix your own formula from powder and bottled water (we're fortunate that we had the kitchen facilities in our room...so cleaning nipples and such were not a problem)...ready mixed formula in cans is handy, but is too heavy for traveling. We found that taking three bottles of water with enough formula to mix (we also had a handy formula container that kept the right amount of formula for three bottles) was enough for our eight-or-less-hour stretches of park time. Usually we used two bottles for formula and one for water which Allan sometimes wanted, especially on hot days.
Most of the men's restrooms in WDW have changing tables. Men, you're out of luck with that old "there's no place to do it in there" excuse.
Take a daily afternoon break... (the nap is as helpful to the parents as for the baby, by the way).
Take turns going to the park, so the baby can have some time in the room without being jostled or riding in the stroller all day. With the grandparents with us, we didn't really do this at all, but in busier times of the year, you might. On the other hand, we did leave Allan with Mom and Dad when we went out for dinner one night.
If you use pacifiers, get some clips and tethers so if the baby drops the pacifier, it won't be lost.
Use the "baby swap" strategy for all of the wilder rides (the mountains, simulators, and the Tower of Terror for example). There's a lot more detail on baby-swapping on the next page.
The louder attractions, "the Legend of the Lion King" for example may be too intense for baby's sensitive eardrums. You might want to skip such attractions, or at least be prepared to protect the little one's ears. One note, when we entered the Great Movie Ride, a CM gave us some hearing protectors that we used on that attraction and a few others.
Avoid over-stimulation...if the baby starts freaking out, go somewhere quiet for awhile (there are several out of the way gardens and nooks and crannies in the parks). With Allan, this was never a problem, but then again he was pretty young to be over-stimulated.
Disney has an unadvertised "sleeping baby policy" that allows you to take your stroller into an attraction with you if your baby is sleeping. In general, stroller's aren't permitted inside attractions, but for a sleeping one, the CMs will almost certainly "break" the rules if you ask. In fact, it may even be possible to go in the handicapped access if you ask IF you have a sleeping baby and need the access to get the stroller in. This DOESN'T mean that you can skip the lines at Splash Mountain with a stroller because a baby in a stroller can't ride anyway. A better example would be the Country Bear Jamboree where a stroller with a sleeping child can be parked in the handicapped area while the family enjoys the show.
Keep the diaper bag light for touring...and replenish supplies when you return to the room. (This worked really well for us.)
Throw a couple of diapers and a pack of wipes in a fanny pack...insurance so you're always prepared since changes sometimes need to be made when you're in a pavilion and the stroller is parked outside. (We didn't do this and we didn't get burned, but I can see the wisdom of doing this when the kids are older.)