If you only have 6 hours or half a day in Cherwell, here are some suggestions:
1. Visit Bicester Village for some retail therapy - around 2-3 hours
2. Explore Blenheim Palace and its beautiful gardens - around 3-4 hours
3. Take a stroll around Christ Church Meadow and enjoy the scenic views - around 1-2 hours
4. Walk around the historic Oxford University campus and its colleges - around 2-3 hours depending on how much you want to see
5. Visit the Ashmolean Museum and learn about art and archeology - around 2-3 hours
Choose one or two activities that interest you the most and plan your time accordingly. Remember to factor in travel time between each location.