WILLIAMSBURG — Colonial Williamsburg and William & Mary are approaching the finish line on separate construction projects that, when completed, will help the institutions honor the nation’s semiquincentennial. At Colonial Williamsburg, work is moving along on the construction of two new complexes — the Colin G. and Nancy N. Campbell Archaeology Center and the Lafayette Arrival Area. William & Mary is finishing its yearlong rehabilitation of the Sir Christopher Wren Building, which dates to the late 17th century. The $25 million archaeology center — a project spearheaded by its namesake, former CW President Colin Campbell — has been in the works for years. The center aims to be an immersive...