Route uses southern coastal road, much quieter at weekends or public holiday. Despite roughly following coast route is not flat - biggest hill in south is Thebaide Hill before St Davids, average around 11% over 500ft climb. Plenty of other small hills, not long but can be steep. At Grenville turn left at lights and head towards Birch Grove and Grand Etang. Climb is easier from this side, longer with stepped climb - get breath back after steep section. Hardest part - climb out of Birch Grove to Seven Sisters, sections of 14% + gradient. Summit at 1,910ft or 580m. Total climb around 4,000ft or 1,220m