If you're into driving around and looking for old houses to walk around and explore then you'll definitely like Mt. Sterling and the surrounding area. There are many, many old homes to look at. Downtown itself is full of them and there are even a couple of abandoned mansions right off of Main Street that will give you a start. That's before you even get to the countryside.
Now, I'm not endorsing Breaking and Entering by any means. If I was, my stalker (who seems to read my pages and reviews religiously) would call me into the local police as soon as this is posted since she's always trying to find something to get me into trouble for. BUT, you can still take pictures and walk around and admire the architecture.
Note: If you do manage to get inside anywhere let me know and send me the photos. I love a good story.
Added note: Once my friend and I were walking around an old plantation house that we thought was empty. Turned out the owner was home. He was getting ready to do some major renovation and was so excited that we were interested he gave us the grand tour.