At that point they were banished from the Garden, and no longer enjoyed the direct presence of God. God remained removed from humanity until choosing to reveal Himself to the Israelites. There is no indication in the Bible about how long a period of time this was.
Well, depends. Genesis 4:25-26 says
“25 Adam lay with his wife again, and she gave birth to a son and named him Seth, * saying, “God has granted me another child in place of Abel, since Cain killed him.” 26 Seth also had a son, and he named him Enosh.
At that time men began to call on [j] the name of the LORD.”
Then Genesis 5:
“3 When Adam had lived 130 years, he had a son in his own likeness, in his own image; and he named him Seth.”
and
“6 When Seth had lived 105 years, he became the father ** of Enosh.”
So, presuming a) that one accepts these stories as literal indications of time as we currently understand it (which is far from a consensus) and b) that the stories are literally true rather than allegorical (also far from a consensus) then one has two possible interpretations.
- If “at that time” refers to the birth of Seth, then one can gather that the time period was somewhere less than 130 years (depending on the age of Adam at the time of the expulsion from the Garden, which occurred before the birth of Cain, that was long enough before the birth of Seth to have allowed Cain to become old enough to kill his brother and be banished).
- If “at that time” refers to the birth of Enosh, it was somewhere less than 235 years (see above related to Adam’s age at expulsion).
As the Bible records God speaking in terms of the murder of Abel by Cain, one would presume that that indicates that at least in that incident, God revealed Himself to humanity. If you want to wait until Noah, then you can play with the math in Genesis 5 to figure out the rough passage of time.***