Now's the question - Where is the Archeology?
First, based on the account, just what would you expect to find? These people built with wood in the middle of a tropical rain forest. There were cement houses, but they were in the north where wood was scarce (due to large populations) (Helaman 3:3-12). Helaman was written during the time of Hagoth who sent several large groups north by ship. Many others simultaneously moved north overland (Alma 63:5-9).
The significance of the fact that these dates closely correlate with the establishment of several Mayan cities is unknown.
So why do most current Book of Mormon scholars cling so tightly to the geography of southern Mexico, Guatemala, Costa Rica, etc. (in spite of having nothing that approaches a consensus)? Because of a conviction among them that the Maya, Olmecs, and possibly the Aztecs are the Book of Mormon people. Yes, while knowledge and the study of these peoples has been of interest, and of value; the scriptures themselves are of far greater worth.
Intense archeology in Colombia (where the cities on the eastern sea, the river Sidon, the lands of Lehi, Nephi, Manti, and Zarahemla were) has been severely limited by violence, drug trade, kidnappings, and two de facto pseudo-government groups competing with the official government. It is ironic that Mormon had to sign a peace treaty with both the Lamanites and separately with the Gadianton Robbers in 349AD to in fact have a peace. I guess in 1,700 years in this area, nothing has really changed (Mormon 2:28). Today, the area around Manti is right in the center of illegal Colombian drug production.
In spite of these limitations, there is some local ancient historical information available. Much of it is interesting, and seems compatible with the Book of Mormon. What so far seems the most interesting is the disappearance of one people, only to be replaced with a much more advanced people right about the time of Christ. Some of the mountain temples in southern Colombia, northern Peru, and in Ecuador also warrant further study.
The Book of Mormon people built their defenses of ditches, logs, wooden towers, and dirt (Alma 50:1-6) (mostly in Colombia). The Jaredites (southern Panama) at the time of their destruction killed at least 2,000,000 who were never buried. There women and children fought, and were fitted with head-plates and breast plates, probably made of brass (Ether 15:15). They also left great piles of dirt from their metal mining, and had many devices of "curious workmanship" (Ether 10:23,27). Many other items that are well described are waiting to be discovered in a scientific, and orderly fashion.
The earth itself shall become a Urim & Thummin (Doctrine & Covenants 130:9), and all things shall be made known. I look forward to further study and field work filling in many of the information holes that are now there. These things will come as we search and ponder.
P. Douglas Kiester, M.D. Feb. 2009