The McKnifficent 6

Hi, I am very lucky to work in education and have the summer off. We spend 5 weeks down in Cornwall every year and this year is no exception On Sat 25th August I am doing a charity walk in aid of RNLI and Macmillian nurses, walking the South West Coast Path from Porthleven to The Lizard and here is my question Is there an easy way to find Geocaches on my route? Also which are the 'must' do caches in Cornwall? I would be extremely grateful for any help Thank you