Hi John,
I'm sure you'll enjoy the Jameson Distillery in Midleton. Within County Waterford, I would recommend that you pay a visit to Lismore. It's only about 30 km from Midleton and will get you on to the main road to Waterford City there.
From Lismore, you could get to the Rock of Cashel in less than an hour by car, so it's a very doable detour. Dungarvan is another wonderful town in County Waterford, about halfway between Lismore and Waterford City. In Dungarvan, you could also walk/cycle some of the
Waterford Greenway.
In Waterford City itself, there are many wonderful things to
see and do, including the House of Waterford Crystal.
Regards,
Eoin