Consider the fact that you never get the "Next Lap Invalidated" message while running the course. There are no laps, therefor you can't really run it freely.
It can't be unlocked for free run but you can use it in time trial which is just one x button press extra (telling it to use the car you're already in), the only problem with Goodwood is that it has rain so karts aren't allowed
good wood is a loop, if you count the non-timed parts, it would be good if we could drive the whole thing, even better a mix of the hill and the rally stage would be awesome!