Starting out at Milford just off the A3 south of Guildford you take the exit off the roundabout signposted towards Petworth. This road (A283) takes you through some stunning Surrey villages (eg Chiddingfold) with some fantastic stretches of open road, twisty corners and challenging sections.
Once through Petworth you're onto the A285 towards Chichester. Again some great twisty sections and long straights with superb visibility.
The route ends at the Goodwood circuit where you can stop, have a wander around and a cup of tea in the cafe then head back and do the route in reverse... Happy days.
Also, I'd recommend a lunch time stop on the return trip at Chris Evan's Pub, The Mulberry, in Chiddinfold.