Gearbox; Last gearbox I struggled with I forgot to remove a piece of cover plate at the back that was stopping it coming off all the way, was held on by two small bolts (8mm heads I think).
Camshaft pulley bolt; Put a screwdriver through the pulley onto the top of the head to hold the pulley still. Put something on the head to protect it, piece of wood or something.
Crank pulley damper bolts; When the box is off, jam the flywheel.