Yes you are right about the Seahenge-Peddars Way-Icknield Way-Ridegwat route. Dr Rudge began his research into a puddingstone trail from Grimes Graves towards Stonehenge back in the 40's or 50s. I'm sitting on the fence but a summary can be seen here http://www.megalithic.co.uk/article.php?sid=2146412012