I think my friends and I have done most of it. We have even gone all of the way back to the beginning of the Trials of Kabr through the jungle area that can be accessed off to the right of the Templar's Well. Took our Hunter forever to get up though at the end since he missed and kept re-spawning at the bottom of the green pit.

Mhm. Agreed. The ghost shells would've been amazing. Now is as good a time as ever to add them in since we're finally getting ghost shells.