For a walk around several of the 'main' sites, including Men an Tol, Maen Scryfa, Boskednan Nine Maidens, Lanyon Quoit and others in a 2-3 hour amble, you might be interested in a short series of articles I did for the Heritage Journal:

Part 1 - http://goo.gl/ryMzf
Part 2 - http://goo.gl/ObnpR
Part 3 - http://goo.gl/ygJF1

Enjoy!