I'm afraid I don't fully understand the rules, even with the comments here.
Could you clarify
- what you mean with "alternate routes" (airducts and sewers)
- is this when I roll a "you find a venti"?
- when to roll on which chart
- when to use the small "DC X to go to room Y" notes on the map
- what happens when your DC is negative due to a modifier
- what you mean with "running across"
Thanks in advance, I want to try it again :)