Sculpture park is between Barnsley and Wakefield.
There's Cannon Hall and the park.
Worsborough Mill museum and park (an old water mill, they still mill flour and bake their own bread)
close to the Pennines.
Leeds and Sheffield aren't too far, York well worth a visit if you are coming up for the weekend
You could even take in a game at Oakwell!
Unusual place to be coming for an appointment though!