The final word in the Times and Seasons on Book of Mormon geography is MICHIGAN.
So far as I can tell, the very last mention of Book of Mormon evidence in the Times and Seasons was on 15 May 1845 (Vol. 6, No. 9, pp. 906-7). It's yet another unsigned editorial. Here is the article in full:
The writer states, that in the town adjoining Cooper, county of Allegan, Michigan, about a mile distant from the fertile banks of the Kalamazoo, is a small hamlet, commonly known as Arnold's Station. The first settlers of this little place, emigrants from the St. Joseph country, found in the township some extensive ruins of what had evidently been the work of human ingenuity, and which they christened the Military Post.
"It consists," says the writer, "of a wall of earth, running northwest and southeast, being about the height of a man's head in the principal part of its length, but varying in some places, as if it had been degraded, either by the hands of assailants or the lapse of time. Fronting the road, which runs parallel with the work, is the glacis, presenting a gentle slope to the summit of the wall, which extends for about the fourth of a mile. Along the entire face of the fortification is a cleared space of equal breadth in its whole extent, covered with a fine grass, but beyond the edge of this the forest is still standing. Such was the aspect of the remains when the first white settler emigrated to Michigan, and it has remained without perceptible change to the present time. The mound is covered with monstrous trees, of a wood slow in its growth, showing its great antiquity, but furnishing no clue to its origin. The popular theory seems to be that the French, who early traversed our country, were the builders; but this, of course, is erroneous. It must have been either the work of a large body of men, or the painful toil of a few. If the former, they might have conquered and subdued any tribe of Indians then in existence; if the latter,
a solitary line of breastwork, without a fosse, or other defence [defense], could have been no protection: and it seems still more mysterious that it should have been placed here, at the distance of a mile from any spring, and with a heavy wood, of a date more ancient than the trees upon the mound in its rear.
If the neighboring Indians are questioned upon its traditionary [traditional] history, the invariable answer is, that it was there when they came-more, they either do not or can not say. That it was the labor of an extinct race is pretty evident, and it probably dates from the same era with the extensive works at Rock River. These latter are, however, of brick, a specimen of which material, taken from beneath the roots of an oak tree of great size, the writer has in his possession."
So if unsigned excerpts in the Times and Seasons are supposed to be evidence of what Joseph and his associates believed (and, as the Mesoamericanists claim, they all generally speculated about the same things), then citing evidence from Michigan must have reflected the thinking of Joseph Smith, too.
I realize the Mesoamericanists think Joseph didn't know much about the Book of Mormon, was merely speculating, hadn't been taught about the Nephites by an angel, etc. While I disagree with them on those matters, I'll assume, arguendo, they are correct. That leaves us with Mesoamerica and Michigan on even ground (although Michigan was the last word). But, as we've all agreed, it can't be both. One or the other has to be, at best, hinterlands.
But think about this. If the Times and Seasons is a draw (which it is if you take the Mesoamericanist argument at face value), then what basis do the Mesoamericanists have for giving greater weight to Mesoamerica?
All we are left with, aside from the hemispheric model which no scholars I know of accept, is a limited geography in either Mesoamerica or North America. Even if you set aside 1) all the scriptural references, 2) all the statements of Joseph Smith and Oliver Cowdery, and 3) all the talk of a promised land, etc., you are left with an area that doesn't fit because of directions, plants and animals (Mesoamerica) and an area that fits perfectly (North America).
So which do you choose?