I'm doing this because I just can't swallow a story posted there.
See, this all happened when I found a sign that points to the Haunted Mansion but had another word originally there, possibly "Gastley", but certainly not Gracey.
Anyway, I asked the open question to all: "what does this sign mean?" Everyone else in the blog-o-sphere is asking the same thing and only two people have a response.
One blog simply mentioned the mansion as "Gracey Manor or Gastley Mansion, depending on your reference" giving no hint as to why they would call it this. Someone else had a reason.
Loosetoon posted a response to my original inquiry found on doombuggies, a website blog devoted "soul-ly" to the Haunted Mansion that does a great job for fans of the attraction. You can read the post here . It's about half way down the page. Basically, it says that a Dr. E. Everett Gastley was a doctor in a stately mansion in upstate New York. It was later discovered he was basically killing his patients.
Now, it would seem logically that this story may have spawned the Haunted Mansion idea with the elements of medical books, the mansion itself being built after Hudson style mansions as mentioned at this link or on this other website and the bride in the attic.
Here's the problem. I did a lot of research trying to find haunted houses on the Hudson. And I found some. The most likely canidate for a ancestor to the Haunted Mansion (based on design and story) could be a house called Wyndclyffe. Look at photos on this page. It looks a lot like the Mansion and is thought to be haunted.
But you know what mansion I can't find on the Hudson? Gastley Mansion.
Actually, I can't find a Gastley Mansion anywhere outside references to the Frontierland sign.
So, let's look for the man, Dr. E. Everett Gastley. Should be easy enough to find, right? I mean, after all the quote from "marseilletarot" (the screen name of the original poster of the info on doombuggies.com) said this about him [quote] "Dr. E. Everett Gastley - noted humanitarian and pioneer of modern medical research and methodology".
Granted it later says this is in the era of 1811 so the research is fuzzy, but surely someone else has written about a noted humanitarian and pioneer of medical research, right? Well, apparently not. Can't find old Gastly anywhere. That is a problem with me.
The poster did leave a reference to where they got their information. All of their entry was in quote and at the end said this. "Haunted America: A Journey Into the Unknown" seemingly giving Haunted America credit for saying all of this.
Problem. What is Haunted America: A Journey Into The Unknown? Another search is fruitless. I did find a book, available on Amazon.com by Michael Norman and Beth Scott.

It's a fictional book. So again I ask, what is Haunted America: A Journey Into The Unknown? A book? Movie? TV show? Documentary? The commentor didn't elaborate.
Okay. Now, my research may not be full. The internet may not (actually IS NOT) the end all end all of research, but here's my list of things I could not find that would shed further light on why a sign would call the Haunted Mansion something else, most likely Gastley Mansion.
1. Gastley Mansion - can't find a reference outside of the Frontierland sign
2. Haunted Mansions on the Hudson - none on the river named after Gastley
3. Dr. E. Everett Gastley - couldn't find him
4. Haunted America: A Journey Into The Unknown - possibly a fictional book
Again, I could end up eating my words later on but I'm still calling B.S. on the story posted on doombuggies.com. There are too many holes in it.
Here's my theory on why that story is on the other blog. They simply worked backwards using elements of the ride to create a story. That's why it fits so well. Unfortunately, real research doesn't back up the claim. The poster just wanted to add to Mansion lore by making up stuff is my hunch.
B.S. to the doombuggies.com story.
Should you find additional research, please feel free to share it here but only if you can back it up with something.
Thanks to loosetoon for the suggestion and research, but I think it raises more questions than answers.