When the Nephite archive was threatened by changing political conditions, Ammaron had hidden the archive in a hill, called Shim. Mormon had retrieved that entire archive from the hill Shim, but then found himself at Cumorah and the whole archive was threatened again, so he buried them in a hill at Cumorah, save a few plates which he gave to Moroni. Now Moroni, carrying with him the records that would be given to Joseph Smith, declared that he too would preserve them by burying them “in the earth.” (Joseph obtained them from Hill Cumorah.)
At this point, Moroni has spent sixteen years avoiding those who were hunting him. He doesn’t tell us the direction he traveled, but if the others had gone south, we may expect that Moroni did not stay at Cumorah either. Given the location where his record was taken from the earth (at Cumorah), it appears that he may have gone north. Depending upon when he heard that his father had been killed, which seems to suggest that he had not left the lands where he could receive that information, he still had perhaps years to travel north before deciding that the end was coming.
Moroni says “my father hath made this record, and he hath written the intent thereof. And behold, I would write it also if I had room upon the plates, but I have not.” The “intent thereof” was to declare that Jesus was the Christ through the medium of the Nephite story. Moroni certainly could more succinctly state that fact, but he did not have the room to write yet another work of the size of what his father had done.