If conditioned air is seeping into the attic in winter it can condense it s moisture out in the cooler layers of the insulation sometimes to the point of dripping through onto the ceiling but it also increases the moisture content of the wood in the attic.
Insulated attic walkway.
Use a zippered insulated tent to keep the enclosure draft free attic tent at 7 attic cover insulator 120.
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.
I would recommend fiberglass blown in insulation rather than cellulose because it is not conducive to insects.
The insulation is 12 15 deep.
The floor must extend beyond the insulation so that the insulation is properly covered.
This is because the horizontal chords are the strongest part of the attic.
Because of this the space is able to supporting heavy loads.
Affix rigid foam insulation to the attic side of the hatch or door.
If you find leaks seal with an appropriate foam.
If you can make the walkway 2 wide it most likely would not be necessary.
If you need a second layer of batting insulation lay it perpendicular to the first layer.
The blown in insulation can be blown right over the ductwork.
Add weatherstripping around the perimeter and a sweep to the door of a walk up attic.
The only means of traversing the attic is by walking the joists.
Attic hatch or door.
Do you just wade through the insulation on your inspection.
If you can insulate below the floors use rock wool or fiberglass batting to the depth of the floor joists.
Pull down stair or ladder.
There is no walkway or landing in the attic.
The attic walkway is constructed so that sits above the horizontal chords of your attic.
With any attic insulation project an all important first step is to air seal the ceiling plane below at every electrical plumbing flue and duct penetration.