According to John Sorenson, highways are now well known in Mesoamerica during Book of Mormon times, but what evidence is there of gardens and chief markets in ancient Mesoamerican cities (Helaman 7:10)?
Cities: For decades the prevailing view was that cities with high-density populations did not exist at all in Mesoamerica. In the last twenty years, however, intensive work at places like Teotihuacan and Monte Alban have demonstrated unquestionably that cities in the modern sense were indeed known during the Book of Mormon times.
Gardens: Indeed, in at least some of those cities recently demonstrated, garden areas were cultivated immediately adjacent to single habitation complexes. At the archaeological site of El Tajin near the coast of the Gulf of Mexico east of Mexico City are the remains of a city that occupied at least five square kilometers at its maximum period, probably between A.D. 600-900.
Chief markets: No one knowledgeable of pre-Columbian Mexico has had any doubt that markets were found in all sizeable settlements, yet until recently, only little attention has been given to the fact that a number of these cities had multiple markets. Blanton and Kowalewski, for example, have noted that Monte Alban had both a chief market and subsidiary ones. For Teotihuacan, Rene Millon identifies one location as "the principal marketplace" and suggests that other markets existed for special products, such as kitchen wares.
These things once seemed problematic in the book of Helaman's casual description of Nephi's neighborhood. They turn out instead to have substance beyond what was known only a few years ago. [John L. Sorenson, "Nephi's Garden and Chief Market," in Reexploring the Book of Mormon, pp. 236-237]