Mongoose,
Go to the General Discussion tab and open the 'Look useful information', you can download a map of the circuit and surrounding area, and choose your very own route. In reality though you'll probably end up following the traffic and the signs.
I've never done it on a bike, but I'd say you'll have to have your wits about you, if it's not gridlock then a lot of people are leadfooting it on what are narrow country lanes, on foot you can at least jump into the hedge.
Keep clear of the Whispering Wood, and cobras, obviously.
H