C Lewis Hind 'Days in Cornwall' published 1907. A great book for anyone who wants to know what was going on in Cornwall 100 years ago....mentions visits to several antiquarian sites.
Just to add to Mr. Hamhead's reply, tis actually a pretty damn good read of a travelogue nature and he does visit a fair few of the Penwith sites. I got lucky and picked up mine for a song on Ebay, but have seen copies locally for ridiculous money.