The only problem I forsee is your set on abandoned abandoned abandoned...
Horror can happen anywhere
take for example something I've got buried in my notes for one day.
Downtown city on a busy night
PCs are sitting in a car at a stoplight. People are crossing when a woman dressed in all in black with a motor cycle helmet stops in front of the car and turns and points at their car. She raises the visor and you can see a scared face as if from burns and she says "I know thee, I have found thee, AND I WILL NOT LET THEE GO!" (line 27 "America a Prophecy" by William Blake) she pulls out a gun from under her trenchcoat and opens fire. If defeated it is reviled that her body is horribly burned from some previous encounter. Otherwise she will continue to hunt the PCs till they are dead.
This is a start of an idea I have of the stopping a cult from trying to destroy the US government where the plot is a very loose interpretation of "America a prophecy" The PCs will find clues that it is all based around this poem but notice that what Blake wrote is not entirely correct.
 I personally find horror a lot creepier if you
1. Put it in a familiar setting with just hints of the weird/supernatural
2. Can play with the lighting (turning it up, down, changing colors etc)
3. Can play with the music and or sound FXs.
Last edited by MortonStromgal; 11-24-2008 at 11:43 AM.
Running: infrequent VtM game
"I'm beautifully hideous!" - Sven the Nosferatu