A point:
Blocked off the buildings to the far left and right to make things a bit less loose.
Changed the doorway from the pipes to house into a pair of windows.
Removed the ledge above cart starting location.
Reopened a wall on the left side now that the building is closed.
Added a wall and half-height wall to the left side of the large ramp.
Opened the opposite side of bunker again, as well as widening the window and clipping to let rollers slide in easier.
B point:
nada!
C point:
Changed how the train is handled after crashing to allow stickies and hopefully put an end to the sound glitch.
Removed the one-way door into C.