tim -

i covered the station nightclub fire for one of the local papers here in ri.
i had never done anything as hardcore as that and haven't since.
about once a month i drive down that road ( about 4 miles from where i live ) and see the vacant lot, all the memorials & big sign, and i can still smell the scene that i photographed a few years ago. it still kind of freaks me out.

i can't make any better suggestions than what has already been said. it isn't easy to document a tragic situation or its aftermath --- for yourself, or for others.

good luck!