http://rustmonsteratemysword.blogspot.com/2011/03/scanning-project-dunwich-call-of.html
Map of Dunwich
Tell me that's not cool!
Well, I can tell you that this bloke apparently came up with the map by himself and admits it's his first RPG town map ever. He points out that "my Dunwich lacked the decrepit, backwoods New England vibe of Lovecraft's squalid little hamlet. Instead, it was more West Coast - probably due to it being as heavily influenced by the movie "Fright Night" as much as it was by Lovecraft".
So I don't belittle the effort but I wouldn't call it very authoritative source either.
Then again, he tells it was in the mid-80s. I think Chaosium's "Return to Dunwich" source book only came out in 1991 and the updated Dunwich book in 2002. (I may be wrong here as there are multiple printings and I didn't trace the original publishing dates that thoroughly.) Obviously the guys at Chaosium also had to make up plenty of stuff so theirs is just another speculative take on the subject. However, they sort of have a licence to define details... And in any case, they often do their homework reasonably well.
For what it's worth, the village map from Chaosium's book looks like this:

It also comes with a large map of the whole area. There's a small-res preview on their site:
http://catalog.chaosium.com/product_info.php?products_id=32So pick your favourite cool.

For something distantly related, there's a real Dunwich in Suffolk, UK. Strangely enough, it's a coastal town which slowly eroded and disappeared into the sea.
http://en.wikipedia.org/wiki/Dunwichhttp://atlasobscura.com/place/lost-town-dunwichSee the small thumbnail in the latter link to see how the coastline moved over centuries. It's not only people who go down under. You can take your town with you.