You could also lightly spray for insects over fiberglass if needed.
Attic walkway over insulation.
I would recommend fiberglass blown in insulation rather than cellulose because it is not conducive to insects.
Exposed floor joists can cause condensation on the inside of the ceiling peeling paint and nail rusting.
Place a 2 inch by 3 inch board directly on top of the joist nearest to the edge of the attic with its largest.
The blown in insulation can be blown right over the ductwork.
Work from the perimeter of the attic toward the door or hatch so that you don t trample all over the insulation you just put in.
Walk to one end of the attic by carefully stepping only on the wooden ceiling joists.
If you can make the walkway 2 wide it most likely would not be necessary.
However if you need to make it narrower i would recommend standing some unfaced blanket insulation on end along the edges of the walkway to hold the loose.