The flashback scene overlaps Michael sitting in the same room where he basically told Connie to get rid of Earl. The last scene of II is Michael sitting outside on the grounds of the compound; he's not smoking (and he is still wearing his wedding ring).
I doubt that we can accurately gauge the year. Some Board members who know the cars of the era may be able to identify the approximate year based on the cars that appear in those scenes. In the hotel scene when Michael strikes Kay, both kids are young, nowhere near college age. The same is true in the scene when Michael closes the door on Kay.
According to the script the last scene takes place when an 18 year old Antony meets up with Michael, but like so many other scenes it was cut so we only see an older Michael sitting in his chair. It would take place in the late 60s.
