As GM, you have the power to run it as you see fit, this includes modifying the adventure to have less rooms, more rooms, rooms in different order, etc. I think mostly if you're worried about staying "true" to the adventure as written, well, don't. What's important is that the group is having fun.
On point 3 I'd say every GM should have some method of keeping notes, whether the campaign is small or large. Find a system that works for you.