TDF viewing in Liege

My family (myself, wife and 2 children) will be fortunate enough to be
in Liege for the prologue TT (July 3rd). Does anyone have any tips on
viewing a prologue? It looks to be 6 km long (through the streets of
Liege, I presume). We'll be taking a train down from Brussels in the
morning. What time do the festivities typically begin (the official
TDF site does not have this listed yet). I do not want to miss the
caravan, as the kids should like this. Looking at last year's
prologue, the caravan did not arrive until 1 pm, with racing starting
at 3 pm.
Also, any tips for viewing with the family? I've googled
through the archives and have found a few, but if anyone has been to
the tour with kids in tow, please enlighten me as to what challenges I
might have in store for me. It does look like Liege has a world-class
aquarium that might keep the tykes busy while Dad is watching the
race.
Thanks,
Jerry