I DMed this adventure today.
I have to say it's excellent.
First of all we have to take in account that it's designed to finish in four hours. The story within four hours gives you plenty of good action, opportunity to RP, and requires some creative thought from the players especially in order to finish their faction missions.
Enough with the good stuff, let's see what could they do better...
A) several skill DCs are not intended for tier 1-3. Should be adjusted a bit.
B) I think a simple riddle could add great flavor in the story without altering the time. Especially if the riddle would come from the rat statue ;-)
C) finally, I would improved a bit the layout. I don't have explicit suggestions, I only know I had trouble finding information often.