What would have been the "skill issue" difference people keep mentioning? It's getting really frustrating how reckless the US military is with the skies. They keep putting people in danger. I can't help but think about the DCA crash due to the continuity of government drills.
There's no reason they should have been flying dark for a drill that night.
GPS NOTAM'd as unreliable on a dark, moonless night?
Fly the ILS approach (or fly a visual approach along the track of the ILS approach backing up your visual with the radio signals). That will give you terrain and obstacle clearance all along the route using locally generated navigation signals that will be entirely unaffected by GPS jamming.
I would 100% (and have) take center's altimeter setting and fly the track of an ILS or localizer rather than "whelp, nothing can be done..." This was VMC; you don't need a local altimeter setting to be safe using the radio navaids; you would need it to legally fly the approach as an ILS approach.
It appears there were too many sources of confusion. GPS jamming, moonless night, busy ATC, not planning on VFR before takeoff, 20 minute short flight, instrument approach disabled, young pilots, mountains, and perhaps others.
Flight safety is about removing entropy and there were several steps which could have been taken, including not flying at all because of forced VFR on a moonless night near mountains.
Dead reckoning (keeping track of position over time without an external source of truth) and radar altimeters are high level features that some avionics do have, but these are expensive and not expected to always be present.
Inertial navigation systems you'd find on missiles are precise enough that if you leave one running on a table in the upper floor of the building you can track the rise and fall of the building as it heats up and grows because of thermal expansion throughout the day (in other words, they are extremely precise).
So it depends.