AS for the map layout, There was a BIG issue. The setting on the roof of the cathedral isn't mapped out. Allright, fair enough, its a DC 10 check to scale the wall and reach the belfry. There doesn't have to be a map for this part. The DC 10 check, however, seems to be rather pitiful. Yes, i can understand that all characters need to reach the top, but they are scaling what would probably be a sheer wall. It would have been better to say that the tower was under repair, and the characters could climb the scaffolding. Really a DC 10 check would have been more appropriate for speed climbing a ladder. Without any time frame for actually climbing, a Climb check would be rather redundant, as it could be assumed that without any constraints, they will take 20 to climb the walls.
However, there are two other entrances that are noted in the text, but buried deep inside. I wasn't aware of them until I had started mapping the game. Since there is no actual action here beyond "get into the cathedral," this is fine. I can deal with the descriptions, and making them up on my own. However, there is no mention of the extra set of doors in the text specific to the entrance of the cathedral, or if players are able to access them. In fact, how did players get up on the cathedral, anyway? There wasn't a staircase. It really wasn't explained. As a result, we, as DM's are lead to believe that players might be able to access these faults. Doing so in one of my players other games resulted in a 15 minute adventure. The boss was dead, and the captives rescued in 15 minutes. My personal game took just under an hour. Two of the monsters are not marked, so i just had to wing it. Two of the secret passages are not marked, and I had not seen the descriptions where the secret passages were. He tells us that there's trap doors leading to another area of the map, but it is "Beyond the scope of this adventure." Excuse me, but when does someone see a door, particularly D&D players, and NOT open a strange trapdoor? Its sitting there, underneath podium. What am I supposed to tell my players, other than an immersion breaking “yea, sorry about that, the map says that its there. It would have been much better to replace the phrase “this is beyond the scope of this adventure” with “There is much evidence that thousands of bugbears lie beyond these tunnels. Dozens of separate footprints are here. You surely will not survive if you go on further, and it is clear that the big bad boss intends to summon them later.”