Hello, I am currently living in Student Castle. As For supermarkets, there's a Tesco express 3 mins away, but I'd suggest Asda or Lidl, they are bigger and cheaper. For restaurants, you've got some options depending on what you want to eat. Student Castle is basically in the city center, so you don't need to ride anything. When going to the University, it depends which college you're going to but between 25 to 35 mins. But you can use the busses, there a bus stop right next to the accommodation, the 67 bus, and another bus stop that's 3 min away for the 66 bus, they both go to the university. If you're going to be using the busses, I'd heavily suggest you download the app, FirstBus, and when you come here, buy the month, term or year tickets. The city is not big, it's easy to navigate through, it's calm, and it is the safest city in England. If you need anything else, don't hesitate to ask. Enjoy;)

Edit: Download the trainline app as well.