Free camping in Petworth
Just before entering the village, coming from Midhurst on the A272, there’s a parking on your right that looks suitable for an overnightstay with a motorhome.
Free camping in Horsted Keynes
A good place for staying is the small pull-in car park bay on the approach road to Horsted Keynes Station. Also you can contact the Bluebell Railway for permission to camp on the field overlooking the station. Charge £3 per night (including the key to the station to use their toilet and shower). A must for any steam, or retro enthusiast.