There are a lot of things to consider here. Will you save money with either situation? Will there be less travel involved? What is the curriculum like in the childcare pre-K vs the elementary school, and will she be ready for Kindergarten at the elementary school if she continues at the daycare? Does the childcare Pre-K have an academic component or does it continue to be a preschool setting with more play?
My kids are in a private school that have a pre-K program but Florida has a free voluntary Pre-K program. Many families struggle to decide the same thing when having an older child in the school and a child going into "K-4" or Pre-K. Some things that they consider are the fact that the VPK programs around are free, hence saving money and the children are famiiar with the settings and the teachers if they have been there previously, but putting the child at the older child's school saves on gas/transportation, allows the parent to have one school to be involved with, and the curriculum follows from year to year, so the children in Pre-K are being made ready for Kindergarten in the school. Also, your younger child might be more ready to begin Kindergarten if she learns the school in Pre-K.
Just some things to consider. It is a difficult decision, but in the long run, I would think that either option would work for the Pre-K year just as it has in previous years, knowing that in Kindergarten you won't have to worry about making a decision. The socialization and academic readiness that she will be getting will be a benefit no matter what you decide.