I walked in this part of Kosciusko National Park in March 2024 with an NPA group led by Richard Thompson. However these notes are entirely my work and my responsibility. They cover the area between Round Mountain and Mount Jagungal in general, rather than focusing on one specific itinerary. They are a supplement to the map, not a replacement. This is a first-hand account except where noted.
The main car access point is the Round Mountain car park, on the Cabramurra-Khancoban Road between Tumut Pond Dam and Tooma Dam. Or you can walk in, from the west (on the Hell Hole Trail from the Tooma Dam area), the north-east (on the Grey Mare Trail, ultimately from Kiandra), and the south (on the Grey Mare Trail again, ultimately from the Main Range area).
There are three trails running from north to south: the Round Mountain Trail, starting from Round Mountain car park; the Farm Ridge Trail, starting from the Round Mountain Trail not far from the car park; and the Doubtful Gap Trail, starting (I believe, although I have not been there) on the Happy Jacks Road (not a public road). All three trails are similar in that they follow parallel and fairly flat north-south ridges. (The Farm Ridge Trail also includes a big drop down to an easy crossing of the Tumut River, and a big climb up the other side.) They all end on the Grey Mare Trail, which runs from the north-east to the south-west across the southern part of the area. All these trails are clear and easy to follow. I know this from personal experience, except that I have not been to the northern end of the Doubtful Gap Trail around Far Bald Mountain.
The only other trail is the Hell Hole Trail, which heads west from the Round Mountain Trail north of Derschko's Hut, making for the Tooma Dam area. I have only seen the two ends of it myself, but they are in good condition, with new NPWS signposts. Others report that the trail is clear and easy to follow right through.
There seems to be little incentive to walk off the trails for the most part. Based on two attempts (a partial ascent of Round Mountain, and an approach to Boobee Hut) I'm pretty sure that the snowgum bushfire regrowth (very common all over the area) is penetrable, although it gets tiring stepping over fallen branches covered with low scrub. There is some impenetrable bossiaea scrub on the north-facing slopes of Mt Jagungal, and some tiring tussocky snowgrass frost hollows along the creeks.
There are two classic itineraries in this area. One is a three-day circuit: Round Mountain car park to O'Keefe's Hut to Derschko's Hut to Round Mountain car park, with an ascent of Mt Jagungal as a side trip on the second day. The other is a longer trip starting from Kiandra or Round Mountain and passing on south to the Main Range. But there are plenty of options.
The best camp sites are at the huts: Round Mountain Hut (non-existent in March 2024, but there is a plan to rebuild it, and the site is good), Boobee Hut, Mackey's Hut (called Tibeaudo's Hut on some old maps), O'Keefe's Hut, and Derschko's Hut. Each has water, good spots for at least six tents, and a pit toilet, except that Boobee Hut has no toilet. The only other camp site that took my fancy was at the Farm Ridge Trail crossing of the Tumut River, although there is no wood there and no toilet. At Derschko's Hut the camping is on the scenic low ridge just above the hut to the east. The Derschko's Hut water problem has been well fixed by fencing off the swamp and making a short track to a good water point protected by a steel grille.
Boobee Hut is the only hut in this area which is not on any trail. We got there by walking downhill from the nearest point on the Doubtful Gap Trail, through scrubby snowgum bushfire regrowth (not too bad). One could also try reaching Boobee Hut directly across country from Mackey's Hut. It's open so navigation would be easy, but there is a creek in the way, and a member of our party who had been that way previously reported that it was soft. There was also a trail (really just wheel-tracks across the snowgrass) coming in from the north, apparently made by a maintenance crew driving in from the Happy Jacks Road. I'm not sure how findable or followable that route would be.
Mt Jagungal is the highest mountain in Australia north of the Main Range. It's well worth climbing. Starting from the Grey Mare Trail, the climb (no rock climbing involved) takes between 60 and 90 minutes each way. The shortest route was to walk up-hill from the weather station west of O'Keefe's Hut, passing to the east around the big cliff to arrive at the summit area. However that did not work for our party in March 2024, owing to impenetrable bossiaea scrub (above head height) above the weather station.
So the best bet now would seem to be the foot track, which starts from the Grey Mare Trail a few tens of metres east of the Tumut River crossing (about 1km east of the Round Mountain Trail junction). The river is just a modest creek at this point. The track was clear in March 2024, going up the east side of the valley parallel to the river, then up on to the pronounced ridge line, then up that to the summit area. I did not climb it myself in March 2024 but members of my party reported that it was good going. There was some bossiaea to push through but the track was always there at ground level.