Definitely the Barrens, with maybe the more refined ones hanging out at a club near Touristville.
I've read the other thread about modifying the ghoul rules. I like the idea of fluid transfer, keeping it to a bite or whatnot. If it takes a mere scratch then you're talking one hell of a baddie. On the other hand, having the runners slog through the sewers in full riot gear/combat armor reminds me of something out of Kirkman's Walking Dead. Definitely a place to play up the description/tension. Breath fogging up the visor, sweat making everything stick, only a flashlight or low-light vision enhancements. Mix a little horror into the run.
I haven't thought about Ravenloft in years! I'll have to see if I can find a copy of Night of the Walking Dead. Thanks for the suggestion.