If you have 6 hours to spend in Denbigh, here are some suggestions for things to do:
1. Visit Denbigh Castle - This medieval castle is a must-see attraction in Denbigh. It will take around 1-2 hours to explore the castle ruins and enjoy the view from the towers.
2. Stroll through the town - Take a walk through Denbigh's charming streets, where you'll find independent shops and cafes. It will take around 1-2 hours to explore the town.
3. Visit the Denbigh Museum - This museum is located in the town's historic courthouse and features exhibits on the town's history, including its role in the Welsh language. It will take around 1 hour to visit the museum.
4. Take a hike in the countryside - If you're looking for some fresh air, Denbigh is surrounded by beautiful countryside. You could take a 2-3 hour hike in the nearby Clwydian Range.
Overall, there's enough to see and do in Denbigh to fill up a half-day visit!