Hi JanieM, I used to live in cornwall, The place offeres everything, however some of the farms have over diversed if you know what I mean. Avoid landsend its crap, be careful driving in mousehole as the roads are very narrow. Just a headsup its not pronounced Mouse Hole, it is pronounced moawzole.
We went on holiday lastyear and visited the lost gardens of heligan, the weren't open when we lived there, and they are well worth a visit.
If you were going for longer I would say pop over to scilly it is a really good dayout.

jamjams x