Hi,
If it is pre 66 then there is a special parking area, they will give you a free pass if you advise them when buying the entry tickets. However the stewards often wave any oldish looking car into this area (It is closer to the track). Try to arrive well before 9am as the traffic can build up especially Sunday. Lots of action throughtout the day, ends around 6-7pm. Food can be expensive in some places. The paddock requires shirt and tie for entry. A lot of people dress in period clothes for the event, mainly Friday.
Lots of good viewing areas but again get there early on Sunday, Friday is good for walking around. It is less crowded at the back of the track, there are free tractor/trailors laid on to take you around.
For B&B I would guess most local places are booked by now. Try Chichester or Arundel both large tourist towns and should have something. Maybe Lancing which is on the coast also. If not check on the Goodwood website.
Anything else send me a PM and I will try and help.
Simon