Depending on weather, wind, snow/ice, be aware that the Obs Snow cat may have opened the "winter cut-off route" from the 4200' pole ( just above treeline). This route "cuts off" the exposed 5-mile grade and the hairpin Cragway turn and re-enters the established roadway at just about the 6 mile marker. Depending on the wind direction, this may or may not be in the lee of Nelson's Crag, but overall is a more sheltered route for the Obs SnowCat to negotiate. Also cuts off some distance ( maybe as much as a half mile).
In the dark of a new moon, headlamps and spares, for sure, prudent to have both Snowshoes and Crampons
The Winter Snow Coach from Great Glen will likely be running ( daytime hours only) and that is a Mattrack-equipped vehicle. Does NOT go to the summit, only to the 4200 foot post. That elevation and location should be obvious. The first 4 miles will be in the trees and broken-out.
The only tracks ( if any are visible) beyond that will be the Obs Cat Tracks. When you reach 4200 foot ( 4 mile park) , you will have to differentiate your best route AKA the broken trail from the unbroken, in weather conditions you won't know til you get there. May not be easy to decipher if it is windblown/drifted above treeline, as the Obs shift change happens on Thursday, weather permitting.
As Kevin said, you may have company, not a bad thing considering the variables.
As to the "buy a pass from Great Glen" question.... Great Glen won't be responsible for you using a dated trail pass outside their declared business hours and off their current "open" trail routes. Know you won't have a leg to stand on with Great Glen if you get in trouble when poaching.
Breeze
