Hoss always amazes me. Hazzardville Horror is a great episode to watch every year around Halloween......although I wouldn't exactly call it terrifying.
The house was on the backlot, just two houses down from Boss' house. The props people did a great job dressing it to look run-down, but it appears in the background of several other episodes in a cleaner state. It has now been replaced by a larger building.
I liked that one too! I'm not sure if the house was used anywhere else. I liked when Rosco scared himself in the mirror and the top of his hat was sticking up and Luke said " Don't worry, you look fine"..LOL!