We don't know enough about the location of the BofM account once it leaves the Old World to have any idea of how to prove its historicity based on site discoveries, and we don't know enough about the overall genetic makeup of Lehi's group and the Jaredites - or about how widespread each culture was - or about how extensively they intermingled with other groups (especially the Lamanites, who didn't keep a record to which we have access) - or about the genetic makeup of the other numerous peoples who were led to the promised land - or any other factors that would help us identify and trace the people mentioned in it. When you discount some of the assumptions of the early church leaders (that truly were no more than assumptions and aren't supported by the book itself) by parsing the text closely, it is next to impossible to make solid historicity claims on either side - pro or con.
Therefore, I don't fret about it. I take it as primarily three men's interpretation of history (Nephi, Mormon and Moroni - with a very little of other individuals) - written in an adapted language different than the spoken one of the time (much like the relationship between written Japanese - borrowed and adapted from the very different Chinese - and spoken Japanese) and then translated into a third language by someone who only had his own vocabulary available to use (meaning the record had to be revealed in the limited language of the translator). Add to that dilemma, words that simply wouldn't have been translatable from one culture or region to another culture or region, and you have almost nothing that can be verified objectively. Add to that the regular assertion that not 1/100 of what was taught was recorded, then that not 1/100 of what was recorded was compiled into the abridgment . . .
If the Book of Mormon was a hoax, it was one of the most elaborate, brilliant hoaxes ever conceived, when evaluated against its own internal claims, but I don't fret it. It's next to impossible to prove it one way or the other, so I take historicity off the table (in my case, by accepting it at face value) and focus instead on what it actually says. That works for me, and I get to avoid wasting time worrying about what can't be proven either way.