I got Dunwich from a local store for quite cheap (surprising) and used it over the weekend. Well, we used the new investigators, the location cards, and whatever else could be used without the board.
Doubling the location cards was a nice touch, but I still think they are going to repeat. You end up visiting the same locations over and over because of how clue tokens are parsed out. I think you probably need 28-35 location cards per area (instead of 14) to compensate for this problem. I still have no idea why the base game only includes 7 per location. It almost seems negligent.
I really want the personal story cards in Innsmouth, but I have zero interest in the rest of that expansion. It's a shame they don't sell those cards separately at least for the base game investigators.