Off at J21 sign posted "M48 Chepstow / Services" - this will take you over the old Severn Bridge. Turn off at J2 (A466) and take roundabout exit to Chepstow (Welcome to Wales). At next roundabout take left turn sign posted "A48 Caerwent" continue for approximately 3 miles to next roundabout then turn left. Approximately 2 miles later take the first right hand turn. The caravan field is the second field on your left. The other entrances can be found several hundred meters further down the same road.
Off at J24 to meet "Coldra Roundabout". Take the Langstone turnoff and follow signs towards Chepstow for approximately 10 miles. Turn right opposite the 4x4 garage, as the dual carriageway ends. The various entrances are about 1 mile up that road.