It’s difficult to make much of the wilderness travel narrative in Numbers 33 without a map. But even a map is only moderately helpful since most of the sites mentioned are unknown to us today (you can find this map online at (http://www.bible-history.com/maps/route_exodus.html).
The long list of forty-two places can be divided into three parts.
Verses 3-18 list cities covered in the account of Exodus 12 – Numbers 12. The places in verses 18 – 36 are not mentioned anywhere else in Moses’ account except perhaps Deuteronomy 10:6-7 where verses 31-33 are echoed. The third part of the list parallels the material in Numbers 20-22.
Why do we have this list when no one knows where most of these places were? Because at one point, people did know where these places were. The account of the Exodus is a true account because an ancient source was meticulous in writing down (note verse 2) the itinerary. Bible writers expected their accounts would be questioned, that’s why they did not write in generalities of historical events, but rather, recorded them in excruciating detail.