The Middleton Inn is a short walk along the Ashley River path from the terraced landscape where the Spoleto Finale takes place. The 2018 festival runs from May 25 thru June 10th.
https://spoletousa.org/ The Spoleto event schedule is announced in January. Middleton Place is the best of both worlds. You are in a living museum and the Inn will organize transportation to festival events and dining experiences. If you make your plans early there are also cost benefits and guarantees that can happen in January and February.