If you are travelling by road from anywhere outside of Devon and heading to the west of Cornwall, the most direct route is likely to include the M5 and then the A30.
Directions From Helston:
From Helston, head south on the A3083 following the signs for the Lizard.
Follow the A3083 for approximately 9 miles passing the Mullion turning and the Lizard Cider Barn on your right. Just after this there is a left turn to Ruan Minor, Cadgwith and Kennack Sands. Take this road which takes you through the village of Ruan Minor and down the hill to Cadgwith (the road is narrow with few passing spaces). As you come into the village there are thatched cottages either side of the road, The Cot is the second cottage on the left.
The Cot has a private parking space close to the cottage, location details will be forwarded with the booking confirmation.