Cornwall is the toe of England, Celtic in accent and history, and organised around small harbours rather than one capital. The north coast takes the Atlantic. The south is softer, with estuaries and sailing towns. You came for light on water. Give it time.
A base in one harbour beats a daily safari. St Ives, Mousehole, Port Isaac and Padstow are known for reasons you will see, and for reasons you will join a queue to confirm. The coast path between the famous bits is the actual luxury.
See
A stretch of coast path
Two coves and back is enough. The South West Coast Path does not need to be completed to be understood.
A harbour town off-peak hour
Early swim, late sitting. Midday in August is a holding pen.
Tate St Ives or Barbara Hepworth’s garden
Art that belongs to this light, if the weather has trapped you kindly.
A tin-coast or fishing story
Geevor or a small museum on a wet day. The industry is the subtext of the pretty villages.