Students should absolutely ease in because what happens is - you get homesick, you don’t know anyone, you don’t know your way around campus and all the other stuff.
That said - ease in doesn’t mean take it easy. It means maybe join a club or two and not 10…maybe study and don’t go out every night, etc. Maybe delay greek life a semester or year.
It doesn’t mean - take less classes, etc.
In the end, the student will do as the student will do because once you drop them off - you’re not there.
Everyone’s kid is an angel but yet 50% are getting drunk all the time 
So it’s really up to them.
Class schedule is dependent upon the major and for some kids, what’s easy maybe rigorous for others, etc.
No one should ever load up the schedule but the schedule should be full - not under average - because you’re paying a lot to send them - and they should take the classes they want to take but knowing it’s not high school anymore.
Good luck to them.