On the Western edge of the Cotswolds is Sudeley Castle, a fantastic castle with 10 different gardens and is the only castle with an English Queen buried in the grounds.
Visit Sudeley on its own or combine with some beautiful Cotswolds villages. Suggest either mid Cotswolds villages of Bibury and Bourton-on-the-Water or north Cotswold villages of Broadway and Chipping Campden.
Of course you can come up with your own suggestions!
Please allow 5 to 10 hours depending on what you decide to do.