Central Cambridge can be a little difficult to navigate in a car due to a slightly diabolical combination of narrow roads, a river, rising bollards and a one-way system.
Since Trinity Street is one way, you’ll probably want to approach from the North, either along Jesus Lane or Magdalene Street.
If you are arriving on a Saturday between 10am-4pm then you must display a vehicle pass to get through the bollards on Trinity Street. Before or after that time, or on a Sunday, the bollards are down and you can drive through to college without a pass. The vehicle pass is only available for Sat Oct 1st — more details will be available in your freshers pack.
If you arrive when the bollards are up and you don’t have a permit, it is possible to park on Queens’ Road over the river, but you will have to carry your stuff down Garret Hostel Lane and over Garret Hostel Bridge (there are a couple of trolleys available to help with moving luggage if you need them), and the parking charges can be quite steep.