As you suggest, everyone knew it was coming, the two questions were where? and when?

The answers were on a "need to know basis", certainly troops were not told until the last moment and even their leaders were not informed until they absolutely had to be.

Once told during the few days approaching 5th June (the original planned date), troops were confined to holding camps - no-one in or out, although some veterans report sneaking out to see a girlfriend or simply go to the pub for a last pint. From these camps men boarded ships or in the case of airbourne troops their aircraft.

Some troops would have some clues to the landing - for example, D company, 2nd Battalion of the Oxfordshire & Buckinghamshire Light Infantry has been assigned the very important job of capturing two road bridges over the river Orne and Caen canal. Initially their commander John Howard was told they would be capturing bridges after arriving in gilders and to train his troops accordingly. Later on he was told the exact details but even then the details were kept from the troops. However, they did practice a precise plan for the bridges - the exact layout of the area was reconstructed in fields and the highly detailed plan practiced repeatedly under the view of referees/marshals who checked that each man made his objective. Had anyone been inquisitive enough they could have tried to figure out where the attack area was.

In the Band of Brothers Winters & Nixon are shown, overlaying flight time/path from practice jumps on to a map to see where they might jump. They (and others) might have done this, but I don't recall it first hand from Winter's book.