The ocean science part is in Menai Bridge. Buses every 5 mins or so. Walking only takes about 20-30 mins to walk to the main building. Take a look on student pad and look up properties in Menai Bridge. To walk to Menai Bridge from the largest block of halls (sorry dont know the name, but they are the ones with the gym, Maes Glas, on the site) will only take about 20-30 mins, or like I said, buses run every 5-10 mins. (or bring a bike)
Parking is free around Bangor
I live in Bangor, so feel free to ask any questions