My advice is always this: Buy the two blue IGN 1:25000 scale maps that cover the area. Look through the gazeteer bit on here, I logged pretty much everything in the environs of Carnac (and certainly all the good stuff).
The maps are really good, every site has a red star on it. You have to get off the beaten track, away from the fenced off Alignements, and to the more remote sites.
Petit Menec, Manio, Kercado, Moustoir... The Burl book is amazing, but also a bit out of date now in terms of roads, directions, condition of sites etc.