If you have 6 hours or half a day to spend in Silchester, there are a few things you can do:
1. Visit the ruins of the ancient Roman town of Calleva Atrebatum. It is located in the village and is free to enter. You can spend a couple of hours exploring the ruins and imagining what life was like in the Roman times.
2. Take a walk in the beautiful countryside surrounding Silchester. There are various footpaths and trails that you can follow, and you can enjoy the views of the countryside. Depending on how long you want to walk, this activity can take anywhere from 1-2 hours.
3. Have a picnic in the Silchester Common, which can be reached in about 30 minutes on foot from the Roman site. You can relax on the green or have a stroll around and enjoy the nature. This activity can take as long as you want it to, depending on how much time you want to spend there.
4. Visit the local pub, The Fox Inn, located in the village, and have lunch or a drink. The pub serves delicious food and has a relaxed atmosphere. Depending on how long you want to stay there, this activity can take anywhere from 1-2 hours.
Overall, Silchester is a charming village that offers a mix of history, nature, and relaxation. With 6 hours or half a day, you can do several activities and have a lovely time.