Hi, Susan!
Stroller parking is available all over the Parks at
Walt Disney World; many rides do not permit strollers aboard, so convenient parking is adjacent to a variety of locations all over the Parks. You can certainly find a place to leave it for an extended period of time.
Bear in mind, though, that these are not "guarded" areas; while you should not expect anything to happen to your stroller, I would recommend not leaving any valuables unsecured while you are away from your stroller.
Lockers are available for a minimal fee at each of the Parks.
Do not forget the value of the stroller as a rolling storage unit! Even if your daughter opts out of using it, you might be grateful to have a place to stash your souvenirs, drinks, and so on, as the day goes on.
Have a wonderful time!
See you later, celebrator,
-Deborah B.