I think with a young baby, you should rent a car. It's so much more
convenient with a car. Hotel shuttles are very limited.
When we went last year, we went back to hotel to take naps each day. It
gave everyone more energy for rest of the day. We usually go to park at 9,
leave park at 1 to have lunch outside the park.
You are going during spring break time, so it will be very crowded there.
So you should go to park early to avoid crowed. We went during Thanksgiving
last year, even before 9