Never heard of this specific place but it fits a pattern I've seen plenty of times down here in New Orleans. Old farmhouse, usually some kind of tragedy in the history, locals start avoiding it and then nobody can quite say why anymore, the original reason gets lost and all thats left is the feeling.
What's the actual story with the Mercer place? Like what happened there? Because "locals won't go near it" could mean anything from a genuine residual haunting to just some ornery old landowner who shot at trespassers back in the 50s and people never forgot.
I've been around enough of these sites to know the ones worth paying attention to usually have a specific account attached - not just vibes. Someone saw something, heard something, felt something they couldn't explain. If you've got that here I'm interested. If its just atmosphere and reputation then probably not worth the drive.