Geographical: As was mentioned above, Limhi's people exit from the "back" of the city through a secret pass. This pass is a way between mountains, and it apparently lead down toward Shilom.
Since the topography suggests that Shilom is at a lower elevation than Lehi-Nephi, the group would be traveling down a valley, perhaps a drainage, that led toward Shilom. Thus they go "round about the land of Shilom." They do not get all of the way to Shilom, because they remain "in the wilderness."
In this case, the "wilderness" would be unpopulated land, but certainly not desolate. There would have been trees and other types of cover, but probably a reasonable path along the bottom of the valley/ravine/drainage - whatever accurately describes the location.
At some point prior to Shilom, when they were apparently still at a safe distance, they were able to "bend their course towards the land of Zarahemla." This suggests that they needed to go around some foothills to arrive at the travel path that would lead in the direction of Zarahemla. Sorenson's map of this routing shows the topography of this area, and depicts precisely this arrangement of mountains and valleys (Sorenson, John L. An Ancient American Setting for the Book of Mormon. FARMS 1985, p. 170).