As you know, the Mesoamerican proponents can't accept the Hill Cumorah being in New York.* You have to realize that the Mesoamerican advocates are promoting an ideology, which is fine. You're of course welcome to believe the same things they do. But ideologues apply disparate burdens of proof, skewed to confirm their biases; i.e., any evidence that tends to support their ideology is fully and easily embraced without question, while contrary evidence must be established beyond a reasonable doubt--and may not be accepted even then.
In this blog, I focus on facts and pursue the evidence wherever it leads. I'd be happy to accept the Mesoamerican setting if the evidence led there, but it doesn't.
Their treatment of Letter VII is a perfect example. The Mesoamerican proponents reject Letter VII on the theory that Oliver Cowdery made up the whole New York setting for Cumorah. They make this claim because the term Cumorah is not found in any of Joseph's personal writings (holographic). But on that basis, we'd have to reject pretty much everything; the only aspects of Church history that he personally wrote about were two versions of the First Vision and Martin Harris' visit to New York. We have to rely on what his scribes wrote, or what was printed in his name, for everything else. But on that basis, there is no reason to reject Letter VII because Oliver Cowdery was his main scribe for lots of other things (including the Book of Mormon) and Joseph not only helped write the letter but included it in his journal and had it republished multiple times.
[I find the claim that Oliver made it up implausible partly because Joseph helped him write Letter VII and later fully endorsed it, but also because Oliver said it was a fact that the last battles took place in the one-mile wide valley west of the New York Hill Cumorah. IOW, he added details that aren't in the text, just as he provided details about Moroni's appearance, what Moroni said to Joseph Smith, and other details found nowhere else. To say Oliver invented all of this is to fundamentally destroy his credibility and reliability as one of the Three Witnesses, and raises an even more serious question about why Joseph fully endorsed the letters. But I'm setting all this aside for now to focus on one specific aspect of the Mesoamerican argument.]
The Mesoamerican argument goes like this. Joseph Smith never used the term Cumorah until September 1842 (D&C 128). Previously, he referred to it only as an unnamed hill, in Joseph Smith-History 1:51. Only Oliver Cowdery referred to it as Cumorah before that, so Joseph must have passively adopted this folk legend started by Oliver Cowdery.
I know that sounds absurd, but that's their position. So let's see what the evidence shows.
[Note: The Mesoamerican advocates also claim David Whitmer's testimony was wrong because instead of hearing the term "Cumorah" for the first time from a heavenly messenger as he said, they insist he actually heard it first from Cowdery. There is zero evidence of that, of course, but it's the only way they can dismiss David Whitmer's testimony. Think about that a moment. When combined with their theory that Oliver invented facts for Letter VII, the Mesoamerican theory depends on discrediting two of the Three Witnesses.]
As evidence for their claim, the Mesoamerican advocates always cite a 1992 paper by Rex C. Reeve Jr. and Richard O. Cowan, “The Hill Called Cumorah,” In Regional Studies in LDS History: New York and Pennsylvania. Edited by Larry C. Porter, Milton V. Backman Jr., and Susan Easton Black. Provo, Utah: BYU Department of Church History and Doctrine, 1992, 73–74. You can't find the paper online except here (but you have to subscribe to Gospelink), but here's the relevant excerpt:
One of my goals for 2016 was to have every member of the Church read Letter VII, just as every member of the Church read it in Joseph Smith's day. You can read it here.
*Some people are trying to make the case that Cumorah in New York and Zarahemla in Central America make sense, but I find that highly implausible for too many reasons to discuss here.