There are two ways to tackle a trip to Cornwall:
1. Ask where the 'best' sites are and hope someone else does the work - you've already managed to get someone to do the search for you of previous recommendations, well done! :-) :-)
2. Check on here for previous recommendations (see above), look at the sites listed on TMA and elsewhere and compile your own itinerary, based upon your time available, likely location(s) and site preferences - some people love lumps 'n bumps, others prefer big old rocks. What's *your* preference?
The fun is in the planning. All else is just exercise :-)