Heaps of stuff in the forum about scripting.
Have a look at the problem map section for: ManfallTlax.
There is a really good series of scripted sequences, some camera work and a moving APC.
Just on the path_corner and monster questions, something I found this morning [that I had forgotten about] was that if you give your Barney, Grunt or Scientist a name, then they wont follow path_corners! Monsters spawned by a monstermaker wont follow path_corners either. And if you want you monster to walk up a flight of stairs... be ready to tear your hair out. It can be done, but some serious patience is required. Better off building a ramp, but make sure it is nice and long.