You know, now that I think of it, if you wanted to keep the ghosts "Sunset Valley" flavored - or any other town, for that matter - it would be (in a modded game) relatively easy to plop a placeholder sim into an empty lot on a new save, use Edit Town to move any households you want to resurrect onto the empty lot with them, Nraas MasterController to "Force Kill" or DebugEnabler to "Death->Die By...", then once you've got a bunch of graves, remove your placeholder sim in Edit Town and change the empty lot's type to Community.
Save it to bin and bam! A graveyard full of the graves of the town's original inhabitants.
Dress it up like a bomb shelter that didn't do its job, or a doomed camp of the last survivors before you.
