"Chillogy" was the only story completely unassociated with either R.L. Stine's Goosebumps books or short stories ("More Monster Blood" did have some ties, if indirect ones, to the book Monster Blood II) - and the only one which actually did not include Stine as a writer.
Karlsville is actually Trinity Street in Toronto, Ontario, Canada. This was the filming location for the exterior of the Curious Goods shop in Friday the 13th: The Series (1987).