Complex sentence: In New Baltimore, the turnpike commission had to purchase land from St. John's Church (which contained a cemetery); as part of the agreement, stairways were built on either side of the turnpike to provide access to the church.
Split into simpler sentences: In New Baltimore, the turnpike commission had to purchase land from St. John's Church, which contained a cemetery. As part of the deal, stairways were built on either side of the turnpike to provide access to the church.