The nearest point of the Red Sea to Jerusalem is over two hundred miles. It is not stated how many days the family spent getting to the Red Sea, but it must have been around two weeks plus the three days. Although they would be hurrying, they would also have been careful not to attract attention.
The expressions “river of water” (v. 6) and “altar of stones” (v. 7) are called Hebrew idioms. In the Middle East there are rivers of sand or valleys and dry river beds called wadi’s that have water in them only in the spring of the year. If Joseph Smith had been writing the book himself he would have said “river” and “stone altar,” the vernacular of his day. Other Hebrew idioms will be identified as they appear in the text.
The altar of stones was undoubtedly a mound of uncut stones in accordance with the instructions given to Moses.
25 And if thou wilt make me an altar of stone, thou shalt not build it of hewn stone: for if thou lift up thy tool upon it, thou hast polluted it. [Exodus 20:25; see also Deuteronomy 27:5–6; Joshua 8:31]
Therefore, the altar was not man-made but an edifice to God constructed of items that God had made.
Later, when the sons return with the plates of brass, they all rejoice and make an offering (1 Nephi 5:9). Except for Nephi and possibly Sam the family did not share in thankfulness unto the Lord at this time. This premise will be supported in the subsequent events.