The translator's Preface to the Book of Jasher, page 5, at this link, shows how Jasher
made the Hebrew plain, that there is no land of nod.
http://www.ccel.org/a/anonymous/jasher/preface.pdf
Also, those who would slay Cain were the heavenly Watchers/judges, who abide in Mount Eden and are set over earth. Abel said YHWH would avenge his blood if Cain killed him, and YHWH works through his judges, who are holy watchers/angels. Cain knew very well that he would be slain, because the Watchers rule over the earth doing the will of YHWH [they are addressed in Psalm 82, and are seen doing their job of ruling for YHWH, over earth, in Daniel 4]. God gave Cain a promise that he would not be slain by the watchers, and bound the watchers to His curse if they did do it. The Watchers didn't do it, and Cain ended up being slain by his own descendant, Lamech, in mistake, according to the Record Book of the Upright.
Jasher 1:32,33
And it shall be when thou shalt till it, it shall no more give thee its strength as in the beginning, for thorns and thistles shall the ground produce, and thou shalt be moving and wandering in the earth until the day of thy death.
33
And at that time Cain went out from the presence of the Lord, from the place where he was, and he went moving and wandering in the land toward the east of Eden, he and all belonging to him.