I am a recent 'explorer' in these realms (both virtual and actual) and have also recently bought the book (but not the T-shirt as yet) to guide my bemused wanderings.
Anyway this weekend brings my first sojourn, and from what I could tell I can think of no better place to start than Avebury. It looks truly spellbinding.
I was just getting all excitied about it and thought I would share it with you