Get a shrub rake with plastic tines and just rake the insulation out of the way until you can see the tops of the beams where you need to walk. Do it slowly as there may be wiring strung across in any direction. Then get yourself a scrap piece of plywood you can set down in areas where you need a work surface or somewhere to kneel.
I just got this rake for attic work:
I might cut the handle down a little shorter but otherwise it works well.
When you're done you can use the rake to replace and fluff up the insulation. (Even when you don't fall through the ceiling, stepping on the insulation compresses it which reduces its effectiveness.)
I also found it helpful to install a few eye hooks so I'd have somewhere to hang my work light without having to worry about it falling down.