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