El Santo Gringo from La Jolla, California:
Hi Enrique. I'm happy you love the Book of Mormon as much as I do. :) Let me answer your questions in brief.
1) The Book of Mormon does not describe hundreds of cities. It describes, at best, dozens of cities. Mesoamerican archeology is much more difficult than the archeology of many other lands. In Israel, for example, there are many documents describing the ancient land, many of the ancient cities were abandoned, and most of the city names were never changed. In Mesoamerica, on the other hand, the Spaniards destroyed almost all of the native documents they found, the Native Americans tended to build new cities on top of old ones, and the ancient names of the cities were almost always lost. That's why most ancient ruins in Mesoamerica have Spanish names, not Native American names. The problem, then, is not that there are no ancient ruins in Mesoamerica. There are many ruins, and
some of them do have fortifications similar to those described in the Book of Mormon.
2)
The Book of Mormon does not describe large-scale use of metal. Rather, it describes only limited use, mostly for decoration or certain luxury items like the sword of Laban. It is not true that Native Americans never used metal, and in fact there are numerous records of metal objects produced in the ancient Americas. It is true that metal was not commonplace, but the Book of Mormon describes metal swords as being very rare anyway. Most of the swords described in the Book of Mormon were probably not made of metal at all. Many scholars think
the Aztec maquahuitl can be considered a kind of stone sword, for example.
3) North-American horses are only mentioned twice in the Book of Mormon. The peoples of the Book of Mormon did not use horses extensively. It is also not true that horses never existed in the Americas prior to the European invasion. In fact, horses originally evolved in the Americas, and
it is not impossible that they did roam the Western hemisphere during Book of Mormon times. However, it seems most likely that horses had gone extinct by the time Lehi arrived in the Americas. The horses described in the Book of Mormon may have been similar animals like tapir, deer, or llama that the Lehites named after the common Old-World animal. This kind of name borrowing is not unprecedented. The Greeks gave an African animal the name hippopotamus (literally, water horse) because it reminded them of a horse.