The most amazing thing about Cornwall if you're from London? It's pretty much next door. We took the trains from Reading and within a few hours it feels like you're in a different country. Instead of urban landscapes the train passes through lush fields and azure skies. But first if you're not from this continent, let me show you a map:
If you have time and a car Kynance Cove close to The Lizard is doubtlessly worth a visit. If you come in the late afternoon you will be rewarded with a stunning scenery and some marvellous light. In terms of equipment I would recommend a wide-angle for landscapes and potentially a nice portrait lens (50mm-120mm) to take some pictures of your loved ones. Bare in mind that the tide levels vary quite a bit so don't let you camera-bag unattended at the beach otherwise it might get wet.