I agree with all of the above. As for walks, Port Meadow, the University Parks, and the Botanical Gardens are well worth visiting. In my first weeks at Oxford I enjoyed visiting every college to see all of the architecture, ancient and modern, and particularly enjoyed discovering the dozens of libraries that are accessible to every undergraduate. Oxford is full of music, and listening to music of many genres might assist. I became enamoured of Baroque music in my first year. The art in The Ashmolean Museum is great.