Missing loads! How long are you intending being down there?

I'd immediately add Chun, Mulfra, Zennor and Lanyon Quoits, Chapel Euny, Sennen, Alsia Wells.

All of which are in Penwith and easy reach of the other sites you listed.

Further afield are Duloe, the Bodmin Moor (North and South) sites, and St Breock Downs.

There's a hell of a lot down there! Try reading some weblogs (mine, Goffick's, Paul1970's, Purejoy's and Mr Hamhead's for starters) to see what can be done in a day.