After Dinner Drinks/ Music in NOTL on a Sat. Night??
If you're going to the Pillar and Post, ask for one of the rooms near the spa. They are larger and nicer.
As for entertainment, probably the only option is the Angel Inn, which is a pub/BandB walking distance (15 minutes?) which will probably have a bar band of some sort, most likely folky. I think the Pillar and Post have a complimentary shuttle that will drop you and pick you up. Worth looking into the shuttle, as the taxi situation is very limited.