What is best route to Oxford from Heathrow? Take bus/train to which station in London, then train to Oxford? Best way from LHR to best station in London from which to depart to Oxford? Thanks.
If you do it by train, you are lucky in that the trains from Heathrow (Heathrow Express and the cheaper but slower Heathrow Connect) use the same station as trains to Oxford: London Paddington station.
The second option is a coach/bus direct from Heathrow to Oxford. These run regularly. Click here for details, then click on "Timetables".
Do not even think of getting a bus from Heathrow into central London, that is even slower than a taxi.
If you will travel with a BritRail Pass (several versions available), then either airport train is covered on that travel day, so you don't have to worry about choosing the cheaper one or about trying for advance discounts on the next leg; pass does not cover buses.
We took the bus direct from Oxford to Heathrow. It was very easy and comfortable. I'm sure the reverse would be the same, and a lot less trouble than going into central London first.
There's a bus that travels to Oxford's main bus station, Gloucester Green, 24/7 leaving approximately every 25 minutes. It makes a couple of stops on the way to Oxford, however, the trip generally takes about 1 - 1 1/2 hours. The fare can be paid directly to the bus driver using either dollars or pounds. We travel to Oxford yearly and that's how we do it.