I think there was about 1 prac in first semester ... it depends what course your gonna do. there was only a 3 hour prac and a 2 hour lecture.
as for travelling late- the latest a class has ever finished for me is 5pm. which isn't that late, its not bad during daylight savings time. during the winter its so cool cause its pitch black and u see no sign of cilivisation until quakers hill.
don't worry, heaps of ppl will be on the train ... u will be fine.