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.
Attic walkway over insulation.
If you displace insulation in order to move around in the attic don t forget to put it back as you leave.
Exposed floor joists can cause condensation on the inside of the ceiling peeling paint and nail rusting.
Walk to one end of the attic by carefully stepping only on the wooden ceiling joists.
You could also lightly spray for insects over fiberglass if needed.
The blown in insulation can be blown right over the ductwork.
I would recommend fiberglass blown in insulation rather than cellulose because it is not conducive to insects.
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.