Just to clarify Goodwood a little for you... there are two major events.
The Goodwood Festival of Speed is normally at the end of June and is a hill climb. So cars go past one at a time. A huge event. It is mostly modern cars, including Formula One
The Goodwood Revival is in September and celebrates cars (and fashion) from pre 1966. It runs on the motor circuit and is a series of races - so you get to see all sorts of pre '66 cars at full race speed. Most who attend dress up in smart attire.
As above, Oxford is worth seeing as are some of the villages in the Cotswolds.
If you need a hand purchasing tickets for Goodwood, do ask.
