Verses 
Mosiah 11:66 And he said unto Alma, Thou shalt go before this people, and I will go with thee, and deliver this people out of bondage.
Mosiah 11:67 Now it came to pass that Alma and his people in the night time, gathered their flocks together, and also of their grain; yea, even all the night time were they gathering their flocks together.
Mosiah 11:68 And in the morning the Lord caused a deep sleep to come upon the Lamanities, yea, and all their task-masters were in a profound sleep.
Mosiah 11:69 And Alma and his people departed into the wilderness; and when they had traveled all day, they pitched their tents in a valley, and they called the valley Alma, because he led their way in the wilderness;
Mosiah 11:70 Yea, and in the valley of Alma they poured out their thanks to God because he had been merciful unto them, and eased their burdens, and had delivered them out of bondage;
Mosiah 11:73 And now the Lord said unto Alma, Haste thee and get thou and this people out of this land, for the Lamanites have awakened and do pursue thee;
Mosiah 11:74 Therefore get thee out of this land, and I will stop the Lamanites in this valley, that they come no further in pursuit of this people.
Mosiah 11:75 And it came to pass that they departed out of the valley, and took their journey unto the wilderness.
Mosiah 11:76 And after they had been in the wilderness twelve days, they arrived to the land of Zarahemla; and King Mosiah did also receive them with joy.
World Location
Commentary
To be consistent with the Book of Mormon, there needs to be a valley one day's travel from Helam. The flocks mentioned in Mosiah 11:67 can literally be any animal. The hebrew use of the term "flock" is not limited to any specific animal or type of animals. Animals mentioned in the Book of Mormon available to the Nephites are cow (ox), horse (***), goat, and dog. Sheep were mentioned in the Book of Ether but not in the later books. Livestock (any livestock - cattle, sheep, goats, pigs, etc.) normally travel about one mile an hour (factoring in rests, grazing, and watering) and can travel 11 to 13 hours a day. Cattle drives consider 10 to 12 miles a day a good day, but one of the longest cattle drives covered about 3,000 miles and averaged 15 miles a day (meaning some days were more and some were less). Pack goats can travel 10 to 15 miles a day carrying packs from 35% to 50% of their weight. They can travel a little more per day just as cattle can. Horses and dogs are long distance travelers that can easily travel over 40 miles a day. Just to determine if the world location is consistent with Mosiah 11:76, the assumption is that the flocks could travel a top distance of 18 to 20 miles a day.
Given the distance limits imposed by the slower animals, this means that the valley Alma needs to be within 20 miles of Helam - just enough distance to cross one ridge or mountain range and go into a valley, as depicted on this world location. Using the same livestock speed gauge for the 12 days to go from the valley Alma to Zarahemla, the distance from the valley Alma to Zarahemla should not be more than 180 to 240 miles (15 to 20 miles a day). The travel shown on the above map is about 200 miles (about 17 miles a day).
