If you are arriving by car - please leave it in the hotel car park, as there is no parking available on the St.Clare's campus. If you are flying into either Heathrow or Gatwick I can recommend the bus service known as "the Airline" http://airline.oxfordbus.co.uk/ as the most convenient (and cheapest) way to travel from either airport to Oxford. Taxi is probably the easiest way to get to the Linton Lodge hotel from either the Bus or the Railway station. This will cost around £10.
With my best wishes