You can even e-mail this page to yourself. The main bus terminal is in City Centre. Show your International Student ID to receive the student rate. You might consider buying a roundtrip ticket to come back to London just in case, otherwise it would cost more for just a 1-way ticket. If you take the bus you can catch the Gloucester Green bus, Citilink, or the National Express coach into Victoria Station.
British rail offers discount passes for disabled travellers.
You will not be able to arrive at Magdalen College until check-in on July 2nd, anytime after noon. Most rooms have a sink and a mirror. There are no study rooms set aside for students. They do have central heating, and they generally shut it down the heating from June until Oct 8 each year. If it becomes uncomfortable for you in your room, talk to either the Oxford Administrator or the Oxford Director about the cold.