JOEL - An LDS anthropologist named John Sorensen has conducted some serious research on the geography of Book of Mormon lands and has come to a tentative conclusion that the Central American area, which includes Guatemala, is the most likely place where most of the activities recorded in the Book of Mormon took place("An Ancient American Setting for the Book of Mormon").
Sorenson claims that the narrow neck of land talked about in the book is the Isthmus of Tehuantepec, which lies between northern and southern Mexico. On his map, Sorenson correlates the river Sidon with the Grijalva River, which originates in the highlands of Guatemala near the border with Mexico.
However, his is only one of several theories as to where it all happened. Other territories which have been proposed have included southern Mexico, Yucatan, Costa Rica, and South America. Some even believe that it all happened in North America, with the land northward in Canada and the land southward in present-day New York separated by the Niagra river correlating with the Book of Mormon Sidon river.
Most agree that the history took place in a relatively small area based on distances and traveling times inferred within the text. I have drawn up my own proposal for the relative positions of lands, cities, and rivers, but I could never suggest an actual site on a present-day map. We simply are not given enough information in the scripture, nor is there sufficient archeological evidence to point to any one area.
Now, if you friend who is going to Guatemala could look around and find something that looks like a Liahona, then we might have something. In the mean time I am not going to be so concerned as to where the history of Book of Mormon happened as I am with the fact that it did happen and the eternal truths I learn from it.