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.
Attic walkway over insulation.
I would recommend fiberglass blown in insulation rather than cellulose because it is not conducive to insects.
If you displace insulation in order to move around in the attic don t forget to put it back as you leave.
If you can make the walkway 2 wide it most likely would not be necessary.
You could also lightly spray for insects over fiberglass if needed.
Exposed floor joists can cause condensation on the inside of the ceiling peeling paint and nail rusting.
Always cover the tops of the ceiling joists to make sure the insulation is deep enough to reach your target r value and to prevent thermal bridging the heat loss that occurs through the wood framing.
The blown in insulation can be blown right over the ductwork.
Place a 2 inch by 3 inch board directly on top of the joist nearest to the edge of the attic with its largest.